Xeelee Sequence

"Do not remember heroes. Do not speak their names.

Remember my words, but do not speak my name.

I have a vision of a Galaxy overrun by mankind from Core to rim. Of four hundred billion stars each enslaved to the rhythms of Earth’s day, Earth’s year. I have a vision of a trillion planets pulsing to the beat of a human heart.

And I have a vision of a child. Who will grow up knowing neither family nor comfort. Who will not be distracted by the illusion of a long life. Who will know nothing but honor and duty. Who will die joyously for the sake of mankind.

That is a hero. And I will never know her name.

Always remember: a brief life burns brightly."

– Hama Druz, de facto founder of the ICoG. Promoting the ethics of child suicide bombers. Yeah, he's that type of person.

Xeelee Sequence is a series of hard (ish) science fiction novels and short stories written by British author Stephen Baxter, which spans billions of years of fictional history (leaving 40k in the dust with its "mere" 10,000), with plots revolving around theoretical physics, futurology, multiple universes, artificial intelligence, faster-than-light travel, and the usual existential and social philosophical issues that tend to go with such works.

Most relevant to /tg/'s interests, though, is that Xeelee is unbelievably grimdark. Like, holy shitballs, final word on the matter, makes 40k look like Sesame Street with butterflies and rainbows in comparison, grimdark. The Interim Coalition of Governance, just to pick one example, is arguably the most grimdark galactic government in all of fiction, even giving 1984 a run for its money, although the Empire of Sol and the Holy Superet Church of Light come pretty close to being a bunch of amoral dipshits. The Xeeleeverse is a place where the concept of hope and humanity has been forgotten so hard that trillions of child soldiers are sent to fight (and get slaughtered) in a war they don't have a hope in hell of winning, and the Coalition knows it and doesn't care. All in all, there is a good reason why the Xeelee used to be the main image of the Grimdark template you see above, for a very good reason.

Plot in a Nutshell

And you thought the Old Ones were ancient. Credits to Frogisis.

To make things short and easy, the entirety of the Xeelee Sequence is centered around the cosmic war between the Xeelee, the masters of 'baryonic' matter (AKA normal matter for us non-scientist plebeians) and the Photino Birds, the masters of dark matter. The war stretched through the entire timeline, from the split microseconds of the Big Bang to the heat death of the entire universe. The war started because the Photino Birds as creatures made from dark matter, wanted to make their home a little bit more comfy, and in order to do this they decide to unintentionally exterminate all Baryonic lifeforms in the entirety of the universe by reducing all the stars into white dwarfs via accelerated cosmic heat death. The Xeelee understandably did not like the idea of some home invader trying to do a home deco around their turf and the battle begin. Yes, you hear us right, the entire war was due to the Photino Birds, for all intents and purposes, searching for a comfier home to live in. Essentially, the war stretched throughout all of time, since almost every major race in the Xeelee Sequence have weaponized Time Travel, and since Stephen Baxter KNOWS his science better than most sci-fi authors, FTL travel has significant affects on time dilation. Granted, his work relied a lot on speculative physics; for example, The Great Attractor has proven to be much less massive than what was thought when the novel was written and has an even larger mass concentration behind it.

But what about us humans? We got our asses kicked by two alien races; the Squeem and Qax, and the latter of the two was so traumatic that it turned humanity into one of the most xenocidal forces in all of science-fiction. Seriously, the Imperium of Man has nothing compared to these assholes, and no chapter in human history was so downright depressing and fucked up as Qax occupation. Humanity has reached to the point that it wants to force the one Xeelee inhabiting the Milky Way to GTFO because they thought the giant Cosmic Ring that the Xeelee was making was a weapon designed to destroy humanity (when in reality the Ring was made by the Xeelee to save ALL Baryonic lifeforms, including humans, and bring them a new Universe). This understandably annoyed the shit out of the Xeelee, so they decided to leave the galaxy. And what did humanity do after the Xeelee left? It collapsed into a wide scale civil war before being unified by another tyrannical regime, and then humanity evolved into different species and fought each other in the period known as the Bifurcation, some humans losing their consciousness in the process of evolution. In the following millions of years, the descendants of humans have annoyed the Xeelee to the point that they got fed up with our shit and decide to lock the entire Sol System in a fourth-dimensional prison while leaving pretty much 99% of humanity to die off. The only humans who are actually doing OK (sort of) are the passengers of the Great Northern, a generation ship that predated all the asshole empires, wound up stuck five million years in the future, and promptly made a beeline for Xeelee-controlled space to hide.

Unfortunately for the Xeelee, dark matter outnumbers and outmasses baryonic matter 9-to-1, meaning that the war was long-decided eons ago. Desperate, the Xeelee decide to create the aforementioned Cosmic Ring to open a gateway to a new universe to escape to. The Photino Birds find this giant Cosmic Ring to be a threat and decide to destroy it, and almost succeed - but in the end, the remaining Xeelee, humans and other baryonic lifeforms managed to escape into the new universe, leaving the old Universe to be conquered by the Photino Birds. Those unfortunate chaps who missed their chance would die a slow and painful death as their universe becomes unfit to uphold baryonic life.

What Baxter should be commended on is the fact that his aliens are truly alien in every sense of the word. None of them are even remotely humanoid and almost all of them (Baring the Silver Ghosts) do not think like a human; with the majority of them bearing chemistry so fucking bizarre it borderlines on theoretical physics for some of them.

Notable Factions

There are multiple factions that spanned the entirety of the Xeelee Sequence. Here are some notable examples.

Xeelee

The main "mascot" faction of the entire series, the Xeelee are the undisputed masters of all Baryonic life. They are made from space-time defects and were born in 10⁻⁴³ seconds after the Big Bang during the Planck Epoch, where the four fundamental universal forces (Gravity, Electromagnetism, Strong and Weak Nuclear Forces) have yet to diverge; ergo physics were still fused under the Grand Unified superforce AKA GUT (Grand Unified Theory). They eventually formed a symbiosis with Bose-Einstein Condensate creatures and allied with the Quagmites, creatures made from Quagma during the Quark Epoch approximately 1 microsecond after the Big Bang. The proto-Xeelee then went to war with the Anti-Matter aliens before winning by tweaking the universal constants so that there was more baryonic matter than anti-matter. Fun fact, that war accidentally created cosmic inflation.

The Xeelee are so far up on the technological scale that they might as well be gods. Their most notable vehicles are the Xeelee Nightfighters, and in most cases the Nightfighters ARE the Xeelee themselves. These chumps make the Necrons look like Orks in comparison. Seriously, not only do they weaponize Time Travel, they also have the ability to use entire galaxies as literal building blocks to create megastructures, such as the Xeelee Ring (or Bolder's Ring to humans). When things get ugly, the Xeelee drop the star-busting pistols and upgrade themselves with gravitational slingshots that can launch a hyperknot of cosmic string, 50,000 light-years in length, with the mass of a hundred billion stars, moving at the speed of light to turn weaponised galaxies into silly string. They are tough enough to laugh off attacks from guns that shoot neutron stars and black holes at 99.c the speed of light, and they come in the untold trillions. These guys are one of the apex predators in all of Science Fiction. They are not to be fucked with.

Photino Birds

The Photino Birds are the main adversaries to the Xeelee and the undisputed masters of all dark life, with absolute mastery over dark matter. Unfortunately for the Xeelee, dark matter just so happens to outmass Baryonic matter 9-to-1, meaning that the Xeelee are outnumbered and out-Dakka'd. First encountered somewhere between the late Planck Epoch and the early Hadron Epoch 20 microseconds after the Big Bang. They are acausal, von Neumann swarms of self-replicating dark matter entities who are not bound by the effects of temporal entropy. All Photino Birds resemble an ovoid/seed-shaped mass approximately 40 meters long and rarely interact with baryonic matter due to being made up of dark matter. The only thing that could kill them are exotic weapons with extreme - and we mean EXTREME - gravitational forces like monopole cannons, the singularity lasers of starbreakers and a cosmic string to the face.

The Photino Birds attempted to destroy the Xeelee Ring, as they view it as a threat to their manifest destiny on making the universe more comfy for them, preventing the baryonic lifeforms from ever achieving a safe haven in which to live. In a nutshell, these guys are selfish dicks who can't even share the same bed with the Xeelee, and instead try to create a complete mess of the Universe instead. All because the Xeelee held most of the blanket when they try to go to sleep. When angered sufficiently, they also use Galaxies as glorified weapon systems by flinging the entire fucking Galaxy at whoever pissed them off. They are responsible for creating a war (to use "war" generously; the slaughter is so one-sided that some books imply the Birds didn't even realize the Xeelee existed) that makes the War in Heaven look like a well-accustomed tea party in comparison.

Interim Coalition of Governance

What can be briefly described as the Khmer Rouge on Bath Salts with its Head of State as Pol Pot on Acid and jacked up to interstellar levels.

The ICoG was one of the major human governing polities that emerged after the Qax occupation, which forcefully deleted most of human history and forced humanity into a multi-billion year PTSD. The ICoG is identifiable by two things: the first is that they are complete dicks that makes Eldrad look like a gentleman, and the second is that they are xenocidal as fuck. The ICoG is one of the most oppressive and grimdark factions in all of science fiction, which is an impressive feat all by itself. The ICoG makes you hate humanity. Seriously, these guys are just evil.

The ICoG spent the lives of countless children, all in a gamble to get rid of the Xeelee from their galaxy and become the dominant lifeforms in the entire universe. They exterminated countless aliens who were in their way, and reduced those who surrendered to a fate worse then death. They commit countless atrocities, not because they are backed into a corner, but just so they can sate their wounded and shattered egos, which never truly recovered from their occupation by the Qax. They are absolute hypocrites and liars that makes the High Lords of Terra look competent. They created such a totalitarian shithole, not because of some pseudo-philosophical bullshit, but because they are a bunch of spiteful pricks who want to make their people suffer. They want to channel their suffering and hate towards the Xeelee, who are trying to save them from the Photino Birds. And what did the ICoG do once they finally drove the Xeelee out of the Milky Way? Did they usher in a new golden age or do they amend their crimes? Nope they immediately fell into civil war before being unified by another tyrannical regime, which also quickly collapses. Seriously, fuck the ICoG, just fuck 'em. When we mean the combined and concentrated Grimdark from all of WH40K still pales in comparison to just the ICoG itself, WE FUCKING MEAN IT.

Artwork of an ICoG Greenship. Possessing more firepower than the entirety of Segementum Solar, combined.

Transcendence

Humanity from the far, far future. Basically the Q from Star Trek, only on steroids and completely unhinged.

So named because of how the multiple transhuman races have 'ascended' to a literal plane of higher existence, kinda like the Matrix if it could reality warp. Oh yeah, you heard us right. Reality warp. As such, the Transcendence was more of a collective consciousness than an actual polity. They were also just as homicidal as the ICoG, with Transcendence Humanity going on their merry murder-spree across the entire galactic supercluster, turning entire Neutron Stars into relativistic ICBMs and even contemplating on condemning every single Human whoever lived or will live into perpetual agony. Just because they can. Chaos wishes it could be this nihilistic when it grows up.

If they are feeling incredibly spiteful today, they may turn a baseline Human into a Quantum Wave Function entity and force them to monitor the universe as it dies from premature heat death. Still, despite all their omniscient and neigh omnipotent power, they finally got the full attention of the Xeelee after they were finally sick of our bullshit and proceeded to Godstomp them back into the literal stone age; trapping the remnants of Humanity on Earth in a four-dimensional hypercube while letting the rest of Mankind to freeze to death.

Squeem

(Pronounced as Scheme)

The oddly named Squeem were a race of eusocial hive-minded squid-fishes and were the first alien race to fully conquer Humanity. Despite starting off roughly the same as Humans chronologically with technology equal to us, the Squeem lucked out by discovering Xeelee tech of which they could reverse-engineer. You can imagine how that worked out when they invaded the Humans.

Due to how unimpressive their base technology is, it didn't take long for the ICoG to completely curbstomp them to the ground and forced them to de-evolve into human-dependent symbiotes. Still, their occupation left a nasty scar for Humanity as it led to the freezing of the Earth's oceans, starving/freezing billions in the process and the following memory-wipe of all Humans to the point that they forgot that organisms once lived in the ocean.

By far the weakest race in the Xeelee Sequence, although this is all relative in Sci-Fi as the Squeem are still powerful enough to kick War-in-Heaven Necrons in the dick and assrape everyone else with their self-improving GUT-driven missiles and stolen starbreaker technology.

Qax

The second alien race to conquer Humanity and basically the tertiary antagonists of the Sequence after the Photino Birds and Humanity itself. The Qax weren't actually a race of militaristic conquerors, unlike other conventional Sci-Fi races. They were actually a race of merchants and traders, the reason why they conquered Humanity right after the Squeem and treated them like shit was because it was just THAT easy. Which kind of gives you a clue on how fucked the Xeelee Sequence is, if the fucking merchants behave like this. The Qax were truly alien in every sense of the word. They were a bunch of 90-meter wide, hyper-individualistic race of convection cells held together by a core of a micro black hole. In a sense, they were a race of living thunderstorms. Due to the fact that they are made of convection cells, they were functionally immortal in the traditional sense as they could easily replace these cells, although their complex biology meant that they had a very low population numbering in only a few thousand, meaning that they place immense value on their individual lives. Nevertheless, because they were living hurricanes that lived off the currents of wind, solar flares, virtual particles and space-time itself, they were individually quite powerful, with only three to four Qax being needed to control the entirety of Humanity on Earth.

Masters of genetic engineering which led to the creation of the treacherous Human Pharaohs and a respectable time-travelling military to boot, the Qax were known to utilize the Spline (Themselves a race of 1km wide living meatbags) as biological warships because its cheaper that way and were known to make their own bootleg starbreakers. They also have weaponised Grey Goo that could breakdown mountains, wipe out every biological compound right down to the bedrock and even turn waste into food. The Qax was finally decimated when a Human tricked one of them into firing a bootleg Starbreaker in their home star causing it to go supernova. They were eventually pushed out of the galaxy by the ICoG, but the trauma of losing so many including their homeworld to their own slaves has made every Qax in the future to kill all Humans on sight as their base instincts.

Silver Ghosts

The only race in the entirety of the Sequence that isn't a homicidal jackass. Seriously, they actually have a dry sense of humour, which brings in much-needed levity in this absolutely depressing saga. The Silver Ghosts are a passive race of spherical aliens approximately five-foot-wide in diameter with a weight of one ton and resembling a floating spherical mirror. So-called the Silver Ghosts because of their...well...silvery skin, a big misnomer is to think of the Ghosts as a single organism. They are not. Rather, like the Portuguese Man-o-War, they are actually a superorganism made out of various individual organisms all cooperating as one to better survive this ultra-Grimdark setting. Apparently, this is due to the fact that the Ghosts had a ultra-secret and ultra-heretical past where they had a civil war which made their Star turn into a Red Giant. By cooperating to the extent where a Silver Ghost can literally choose which cell to die - making them functionally immortal - the Silver Ghosts became a post-scarcity society.

Inside a Silver Ghost host a fleshy substance with a core strangely resembling a Human fetus. Oh, but it gets weirder. Their silver skin - in itself an independent organism as aforementioned - fucks around with Planck's Constant (Ergo: it was a Planck-zero layer, a sandwich around a zone where Planck's constant was lowered), making their skin ultra-reflective to the point of being immune to ALL DEWs. In fact, it was considered normal for Silver Ghosts to literally sunbathe in the core of a star. At the start of the Third Expansion, the Silver Ghosts were unfortunate enough to be in the way of the growing ICoG despite occupying a significant chunk of the Perseus Arm in the Milky Way Galaxy. Despite being passive, the Silver Ghosts weren't slouches in combat, especially when led by the Black Ghost. During the war, the Silver Ghosts were using the gravitational energy of entire star clusters to fuck around the universal constants such as the Lightspeed Constant (Cockblocking Humanity from going FTL) and the Electromagnetic Binding Forces (Makes everything baryonic including Humans; brittle). These stars were quickly used up like giant Double-A batteries and replaced not long after. They were also doing a lot of whacky shit outside of your typical time travel shenanigans such as Planck teleporting entire planets and battlefleets as weapons and even entertaining the idea of creating a Force Vacuum Collapse to destroy the entire fucking universe if need be. Yeah, and do take note that they are the second weakest race in the Sequence.

Still, being the nice guys and all, it still didn't stop Humanity from wiping out the Ghosts and farming their skin for shits and giggles. This is the Sequence, only the assholes survives.

Shortlist of Grimdark Shit in the Sequence

It's like the Sliding Scale of Idealism vs. Cynicism but the control panel has completely broken off.

This is just a small taste on why the Xeelee Sequence is a pants-shittingly terrifying place to live in.

It is already a foregone conclusion that the entire Universe will die a slow and painful death.
Before the really bad shit starts happening, humanity was fucked up from the start. The Holy Superet Church of Light raised a girl called "Lieserl" as one of their projects, innocent enough right? Well she was infused with nanomachines which caused her to grow to the age of 90 years in 90 days. She was downloaded into a virtual copy, dropped into the sun, to monitor the Photino Bird threat and forgotten about.
Empress Shira, a girl from a Qax-occupied future, subjugates Earth and makes them believe in a bullshit religion worshipping the sun, in an attempt to not get occupied in this timeline. Well her Empire was the most oppressive and amoral empire yet. For instance, one of her guards found an unauthorized colony of humans living out of the Solar System, and disassembled it, putting all of the inhabitants into stasis pods. Alpha Centauri, one of their colonies, didn't handle the situation any better, unleashing a data-virus on the Earth and hitting it with asteroids, causing tsunamis until Shira gave up. She still didn't prevent Earth from being occupied by the Squeem or Qax. Also, the bad shit is only getting started.
The entire Human race has its culture and history destroyed by the Qax in order to pacify and turn them into useful slaves. Literally, we mean using nanites to kill plants and destroy fossil records. Qax blow bubbles into the bedrock called Conurbations which are basically hive cities shaped like domes and absolutely MISERABLE to live in.
- Oh did we forget to mention, Conurbations are meant as temporary structures. When the Qax left Earth, no new Conurbations could be built. This resulted in Conurbations becoming unlivable, fucking fantastic.
The Qax occupation deliberately altered the Earth's biosphere, causing mass extinction and pushing the human race on the brink of catastrophe. The Squeem on the other hand, dropped bio-engineered plagues to extirpate out a large segment of humanity's population, and froze the entire fucking oceans using electricity in a process called "polar cubic ice".
- The Qax leaving did not end happily for humanity. As seen above, the Qax were the ones who made new Conurbations, and also provided food to all the humans. People were homeless and starving, trying to grow food in the nanite-fucked ground, but they couldn't. Also the Green Army deliberately withheld rations from the people.
Human traitors who sold out their race to the Qax are given genetic engineering to become immortal 'Pharaohs'. The immortality, however, is random especially for their children, as sometimes their kids are stuck being an 8-year-old forever. Or, in some cases, stopped growing in-utero, forcing the mother to commit an abortion.
The Silver Ghosts also abducted humans to keep as samples for experiments. Alien Joseph Mengele, hurray. One of their subjects, labeled "five" was raised differently from humans. When she was extremely young, some human samples who broke into the facility had the audacity to subdue and rape her. What a warm welcome into humanity.
When the ICoG exterminated the Silver Ghosts, they kept some of their genetic samples so they could use their skin for augmented purposes. Ergo, they reduced an entire race into cosmetic farm animals to be harvested and the humans wear them as skin. This applies the same to any aliens exterminated by humanity.
Humanity went on a mass universal xenocide campaign before entering a 500,000-year siege in the Lanikea Galactic Supercluster. You'll be thankful when the Xeelee put an end to humanity's brutal curbstomping of every Xenos species.
The way the Xeelee exterminated humanity was unbelievably brutal, they planted a Xeelee Flower in every star and covered it in XCM (Xeelee Construction Material). While everyone froze to death, the Xeelee provided booths for humanity to escape into (because they aren't a bunch of fucking monsters, they were trying to stop humanity's murder-rampage), and a four-dimensional prison for them to rot in.
- Going on the theme of humanity's murder-rampage, they sent a Xeelee Nightfighter back in time to interrupt Michael Poole's wormhole project, and also kill humanity by firing thousands of diamonds which weigh several thousand tons. Michael drove the single nightfighter back to the galaxy's center with its tail between its legs, but the Nightfighter made sure that humanity would never spread throughout the galaxy and cause pain and misery for themselves and any other species, which the Xeelee was honestly right for doing.
When the Adeptus Mechanicus stopped innovating, it's because of incompetence. When the ICoG stopped innovating it's because there's no point in this Grimdark future. It makes no difference if you send child soldiers or mechas against the Xeelee, because they'll kill you anyways, so they just send child soldiers because its cheaper.
- Also, the Guild of Engineers are so wung-ho on standardization throughout the galaxy. That means technology stood static for tens of thousands of years. It doesn't matter anyways, because the Xeelee are capable of fucking up even the best technology a human can make.
Throughout the ICoG's history, the rate of interservice abuse was so extreme, that the commissaries (Their version of the Commissar) routinely beat their conscripts to death. Do take note that all these conscripts are children. So expect a LOT of child abuse. It gets to the point of being borderline uncomfortable to read.
- In the short story "Riding the Rock," the Interim Coalition of Governance took over a world and proceeded to condition the children into child soldiers. They took a school, which honestly was like Pol Pot's S-21, and forced the children to do unspeakable things: they beat them to death, forced them to fight, and tried to "breed out their emotions" to prepare them to fight the Xeelee.
- Because the ICoG has time travel if you did an oopsie, every single variant of your past, present and future self will either be tortured to death or get a summary kicked to the jaw for a crime you have yet or have not commit.
- One of the highest honours a parent would receive is if their child were to be inducted into what is effectively a child suicide bomber corp.
- Hama Druz was a bitch to the highest degree. He organized a witch hunt on all the Jasofts and Pharaohs (human collaborators who served the Qax), even though they were the last remembers of Earth and only serving the Qax out of necessity, and most Pharaohs were TRYING TO HELP HUMANITY DURING THE RULE OF THE QAX. Hama, being the racist twat, proceeded every abhuman species which evolved in the universe. Needless to say, most human settlements were less-than-thrilled to join the Third Expansion. Also did we forget to mention, Hama Druz continued the Extirpation, which was deleting every bit of old data** like how the Qax did, honestly what the fuck.
Humans in the ICoG are indoctrinated by birth about the Druz Doctrine and, unlike the half-assed attempts of the Imperium to issue autocratic control, the ICoG goes full 1984 and have near totalitarian surveillance right down to control of your timeline.
- In fact, the rate of indoctrination was so extreme, that even the thought of going against Coalition doctrine convinced one of the characters to nearly commit suicide out of pure instinct.
When there is rebellious dissent, the Imperium uses the Adeptus Arbites and rarely, a small Crusade to crush them and retake the world. When there is even a potential tinge of dissent, the ICoG dump an entire moon with the population of tens of billions into a Gas Giant; just to make a statement.
You'll be living in a barracks ball: a spherical conurbation where you live with your cadre of child soldiers, where you'll ride a Greenship straight to your death, or you'll live on a rock: a filthy and miserable environment where you'll work until you die by the hands of the Xeelee. So many children are expended, their names had to be etched on the wall via nanotechnology. Talk about literally becoming a statistic.
If you somehow manage to avoid being conscripted into the Green Army as a child soldier, then you will be living in a coalescence, a literal human ant farm built out of faeces with a million people crammed into a space the size of a city block. They make the underhive of a Hiveworld look pristine in contrast.
- Coalescences half a million years later evolved into even more nightmarish versions, with humans preforming functions with their own bodies such as recycling air, recycling shit. Yes, we mean post-humans swimming in shit and converting it into food.
- These nightmarish environments evolve wherever there is massive overcrowding and nowhere else to go. This can happen to any society, and evolved in Rome, Mars, and on a Xeelee structure called the "Wheel" which is a smaller dollar-store knockoff of Bolder's Ring.
Many of the ICoG's child soldiers are bred from either vats or 'breeders' from Coalescences. Breeders are human Martian females that are pumped with so many hormones and genetic engineering that their stomachs balloon-up with the number of babies they are carrying. Breeders are essentially impregnated the moment they menstruate and continue the rest of their lives shitting out ~~babies~~ child soldiers until they expire. Human females in the Xeelee are reduced to birthing sows. Yes, this is state-sanctioned child rape. Daemonculaba, eat your heart out.
The ICoG forbids ALL forms of heroism as it runs counter to the Druz Doctrine and risks splitting humanity apart due to the dangers of individualism and egotism being a potential byproduct of heroic deeds. So if you wanna be a goody-two-shoes and save someone by ignoring orders like Luke Skywalker or sacrifice yourself for the greater good like Sanguinius, the ICoG would go back in time to arrest you, charge you and than execute you if you're the former, or erase your existence from history if you're the latter, or do both if they are feeling particularly spiteful today. The ICoG wants you to die like a bitch, so you will die like a BITCH.
The ICoG's motto is "A brief life burns brightly". They mean it literally, with the average lifespan of a human being measured 16 years of age at most, as the majority of humanity are child soldiers bred to die in the front lines. Combine with the mass state-sanctioned child abuse and child rape, the stripping of identity and the fact that the concept of the nuclear family is pretty much extinguished, you will die a brutal and ignoble death, a death which will be reduced to a statistic and quickly forgotten. They make even the callousness of a Krieger and an Iron Warrior look like a bunch of woodland hippies in comparison.
- On average, the life of a Green Army soldier measured in just 1.7 missions before death, with 10 billion child soldiers dying each year. It was estimated that 30 trillion child soldiers died in asteroid trenches surrounding the Milky Way's galactic core for over 20,000 years, just to make one Xeelee to fuck off.
In one short story, during the Squeem Occupation (The first alien occupiers of Old Earth), a couple of human refugees decided to make a break for it. They modified an asteroid by putting a GUT-drive on it and turning it into a spaceship before escaping the Solar System. The Squeem took note of this and launched a GUT-missile that could tracked them, theoretically, forever. Since missiles have a better thrust-to-weight ratio, it would eventually catch up. In order to avoid being turned into stardust, the humans slowly increased their velocity, in which the missile would respond in kind, creating an intergalactic cat-and-mouse chase. The faster the ship travelled near light speed, the greater the G-force and inertia. Eventually, slowly but surely, the crew of that ship would experience every bit of their bones and organs slowly breaking by the crushing G-force. Some of the humans commit suicide whilst others uploaded their minds on a computer. Eventually, they manage to get rid of the missile via baiting it in a black hole's event horizon. Unfortunately, this is the Xeelee and Stephen Baxter knows his shit. The faster you go, the more extreme the time dilation. Ergo, once the humans finally got out of the chase, several million years have passed. By this point, the Photino Birds have won and they enter a dying Universe.
In another short story, a Human crew encountered a derelict ship, whose hull is seemingly made out of human bones. Once they entered the ship, they realised that the ship was housing a community of degenerate humans that got lost in space. How did they survive for so long without any agriculture? By turning their women into a literal food vending machine. Yeah, turns out that the skeleton decoration on the ship's hull were actually baby bones; they literally reduced infants into ration-packs and farmed meat produce.
- Baxter has a tendency for flesh-ships. Near the end of the novel "Raft", the main character gets exiled to the Boneys because nobody else would take him. Well, the Boneys are a fucking ball of flayed skins and skeletons floating in space. These people live in a mini world made of corpses, and eat discarded corpses from the Raft and Belt societies. The whole place smells like rotten corpses, and it's also described as absolutely filthy.
- Keeping in theme with the flesh-ships, Spline ships are massive asteroid-like meatballs a few kilometers wide. It's said to feel like being swallowed, being in a Spline ship.
One of the ICoG's distant descendants, the Transcendence came to an endpoint, of which they concluded that humanity = suffering, and that it would instead reach into every timeline of every human that has ever existed, would exist, or could exist and just annihilate them; forcing every human who ever lived to experience all the pain and suffering of every other human who ever lived, over the course of quadrillions of relative years. They consider this as 'paradise'.
Configuration Space from "Reality Dust" is a bunch of bacteria in the Callisto ice neurally and chemically communicating with each other to form a new universe: an island with a mountain of order, and a sea of entropy. This island seems pretty nice, but the ocean is all black and it melts whoever touches it by the power of entropy. There's a community of degenerate humans in this universe which are basically zombies.
- A character was downloaded into this space, and started doing normal shit like eating the grass. She touched the water and melted her fingers off. She saw one of the "zombies" and explored the forest. There, she found even larger, more depraved zombies in the forest.

Things that make the Xeelee Sequence Absurdly and Horrifyingly Overpowered

Unless you're Marvel/DC, Doctor Who or the Downstreamers, this is the most appropriate fate of whoever mess with these fuckers.

As you know by now, the Xeeleeverse is not the nicest place to live in; arguably one of the worst settings you could ever conceivably have your unfortunate sorry ass be dropped in. Yet, it is the setting's power capabilities that would truly catch the eye of most of you readers here. There is a reason why the term "Xeeleestomp" is a thing. These guys curbstomps The Culture. Comparisons between WH40K is needed in terms of context. Here is a shortlist that showcase just how overpowered the Sequence truly is:

Every single faction, even the weakest ones are Type 4 to Type 5 civilizations on the Kardashev Scale. To give you some context, the Imperium of Man is considered a Type 2 Civilization, which means that they control the energy output of multiple star systems, whilst the Necrons and Ancient Eldar are an early Type 3 who controls the energy output of a single Galaxy. In the Xeeleeverse, factions like the ICoG and the Qax - who are Type 4s - are easily harnessing the energy output of Galaxy Clusters.
- To give a better context, the Silver Ghosts, easily one of the weakest factions in the Sequence, is generally agreed among multiple versus forums to be able to utterly steamroll the entirety of the 40k universe, combined.
Every A.I. and supercomputers in the Xeeleeverse use CTC (Closed Timelike Curve), essentially meaning that they could travel back or forwards in time to achieve unlimited processing.
- The Xeelee themselves one-up this by having the Anti-Xeelee, an A.I. construct made of probability quantum wave functions and is a fixed point in time, meaning that it exists in the beginning, present and end of the Universe, all at the same time.
- The Xeelee' equivalent of a supercomputer is a supermassive black hole. Yes, they use the core of Galaxies as a desktop.
Every FTL ship is effectively a timeship. Time travel is heavily militarized with ships from various factions going back in time to accelerate the civilizationary progress a hundred-thousand fold or grant their ancestors effective precognition.
The Space Marines use miniature rocket launchers as standard equipment, whilst other factions use molecular-disintegrator beams and monomolecular shuriken cannons. Compared to other Sci-Fi universes, that seems over-the-topped. In the Xeeleeverse, the ICoG's equivalent of the dudes in T-Shirts carries Flashlights that could turn boats into slag and kill thousands of humans in seconds. Their Flamers act more like Meltas, flash-frying and carbonising people in a near-instant. Their 'Bolter' equivalents are guns that fire GUT-rounds. GUT stands for Grand Universal Theory, or in layman's terms, they are rifles that fire pellets with the mass-energy density of a Big Bang (approximately 10^-36 seconds at the beginning of time) - ergo, Big Bang Rifles. For anti-air purposes, the Green Army ground forces use Monopole Cannons, that fires one-dimensional, space-time defects at near the speed of light as their RPG equivalents. They also have reverse-engineered Xeelee Starbreakers that could rip apart anything, up to and including, entire Stars.
The average joe in the ICoG wear skinsuits which could affectively negate the melta-level effects of their flamethrowers. Have fun imagining a couple of guys that are almost completely immune to Melta weapons.
Basic GUT-ship and vehicle weapons from the ICoG involves firing black holes, neutron stars and monopoles at near the speed of light. These black hole cannons mind you, could disrupt the event horizon of a galactic core. The ships themselves could tank a point-blank burn from a Magnetar Eruption and are protected by a Gravastar Shield, which is a pocket dimension that defends them from FTL foreknowledge and other forms of conventional or physical attack.
Your average tweeb in their mother's basement can make wormholes for shits and giggles.
The Imperium considers the Siege of Vraks as one of the largest and longest form of trench warfare in their history. The ICoG use entire galactic superclusters as trenching material on their off days.
The Silver Ghosts had Quantum Gravity AI that was both acausal and allows it to see the future. Unlike the Eldar Farseers, they are always proven right with flawless precognition.
- They later one-up themselves by creating a Planck Zero AI, which, as its name suggests, lowered Planck's Constant to zero via shoving it in a pocket universe. The A.I. had infinite computational power and could make these computations in zero time.
- When the Silver Ghosts got their shiny skins flayed by child soldiers and hunters, the Quantum Gravity AI was taken and implanted into weaponized humans who could see into the future. In the story "Gravity Dreams," nearly a million years in the future, a boy heard the transmission of a girl in another universe, the same universe of the book "Raft," which was reaching the end of the stelliferous era.
The Silver Ghosts used teleportation that deliberately increases Planck’s Constant, which in turn, increased the uncertainty principle, which in turn, makes the manipulation of the probability of a given object's place absolute. This range from a single person to entire planets.
The Silver Ghosts could rewrite the laws of physics. From weakening the electromagnetic force (Thereby increasing the lightspeed constant at the expanse of shaking matter apart) to increasing the strength of gravity by a factor of a billion.
The Xeelee Nightfighter 'wings' are composed of space-time defects called "Domain Walls" which stretch for tens of kilometres and are constructed from one-dimensional singularities. The materials for the ship itself are called...well...Xeelee Construction Material (XCM for short)(Also called Xeelee Hull-Plate). You know those Big Bang Rifles that the ICoG's basic grunts carry around as mentioned earlier? Yeah, they do as much damage to these Nightfighers as a Stub Gun could do to Terminator Armour.
The Xeelee lives off on the event horizons of supermassive black holes. Only extreme gravitational forces or their own Starbreakers could actually harm them. You know the XCMs? Yeah, they violate the Pauli Exclusion Principle, which means all of its atoms share the same quantum state; able to absorb energy with a 100% efficiency. Essentially meaning that using direct energy weapons or exterminatus-level bombs like a Cyclonic Torpedo would do nothing and in fact, may actually heal them.
- An example of this is when a human used a literal XCM umbrella to shield himself from an exploding stellar nova.
Their Nightfighters could stay motionless to going at near the speed of light in a blink of an eye. Their most basic and common weapon, the Starbreaker as mentioned before, are basically black hole lasers that open a wound in space-time - which are also cherry-red in colour due to electromagnetic red-shift - that could blow up a star system for the kicks.
The Xeelee could reshape and move entire galaxies like lego set-pieces. The construction of the Xeelee Ring was a one-dimensional singularity that was turned into a cosmic string and was big enough to start pulling Galaxy Clusters into its gravitational well.
The Xeelee have weapons that could vapourize weaponized galaxies. These are essentially cosmic string anti-air missiles, thousands of light-years wide and moving at over half-light speed to bisect entire galaxies.
The Photino Birds could use said aforementioned weaponized galaxies as anti-armour weapons.
The Photino Birds lives off the gravitational and stellar energy of stars. Ergo, they started a mass reconstruction program via the mass accelerated heat death of the Universe, turning every star into a white dwarf, whose long lifespans in the hundreds of trillions maximizes the Birds' comfort and reproduction cycle. This contradicts the Xeelee's way of life as they need the event horizon of a black hole to sustain themselves. Accelerated heat death = no supernova = no black holes. Ergo, war begins.
- The Photino Birds's reproduction is a form of self-cloning or replication. They are in effect, Dark Matter von Neumann swarms.
The Photino Birds were creating an inertia bomb big enough to shake the Xeelee Ring - a ten million light-years wide construct - into pieces.
The Photino Birds was making the Xeelee their whipping bitch. Take that into consideration. In other words, they made the strongest beings possibly made out of Baryonic matter flee the universe with their tails in between their legs.
There are also the Monads which are the 'Gods' of the Xeeleeverse. They live in the 'Bulk', which is the space between universes and are so god damned powerful, they view both the Xeelee and Photino Birds in the same way the Xeelee and Photino Birds view humanity.

Xeelee Sequence

Contents

Plot in a Nutshell