Fenris

"There are no wolves on Fenris."

--Popular saying during the Great Crusade.

Even the tyranids would need a blanket here.

Fenris is a frozen little hellhole in Warhammer 40,000, most notable for being the home world of the Space Wolves. Named after the ancient Viking wolf monster involved in Ragnarök (because the Space Wolves are also Space Vikings, at least at first glance), Fenris is located in either the Segmentum Solar or the Segmentum Obscurus. The Imperium in all politeness, classifies it as a Death World, meaning that everything in the planet's biosphere is lethal and will always try to kill you and most of the times succeed. This makes it the ideal place to recruit for an army of space vikings.

Fenris is composed of a single continent called Asaheim (Literally translating to Home of Gods in old Norse), with hundreds of islands in its vast world sea. Those parts of Fenris which aren't completely frozen over can only sustain human life for no more than a few minutes, and alternate between being frozen and undergoing earthquakes. The Fenrisian wolves are among the most dangerous predators in the galaxy, as they can reach the size of a full-grown horse. The dominant sea life are octopi-like monsters called Kraken, and they have tentacles that can reach miles in length -- some paranoid types have claimed that these may actually be stranded, devolved remnants of a past Tyranid invasion, just as they claim is the case with the notorious Catachan Devils. There are also bipedal, anthropomorphic... things ...walking about the snow of Asaheim that the locals refer to as trolls, as well as the Wulfen- abortive Space Wolf neophytes that have devolved into wolf-like monsters. All in all, it's one of the deadliest planets in the galaxy.

And the Space Wolves love every minute of it.

It has been invaded only three times:

• First in M33 by the Thousand Sons and Magnus himself, who lured most of the chapter away, brought a million-numbered army of mortal cannon fodder, laid siege on the Fang, successfully broke in, destroyed a Wulfen curse cure, killed a whole bunch of awesome guys including the current Great Wolf and almost including Björn, and then teleported away with his Thousand Sons and their ships, avoiding any major loses (aside from that massive army of mortals, which he left behind as a distraction). Space Wolves somehow decided they won. (Mostly because the Leader of the Wolves REALLY REALLY hurt Magnus. Space wolf style! Basically he beat Magnus down really hardly after falling off the massive mountain that is the fang, Punching him into a wall, ripping off his skin revealing a humanoid cloud of light, making Magnus yell out in pain and almost ripping out Magnus's eye. Magnus recovered in a spectacular way though. That being catching the Wolf lords first then literally annihilating his soul with a flick of his wrist. THOUSAND SONS FOR THE WIN FURRY FUCKS!!!!)
• Second one was during the Age of Apostasy by the mad cardinal Bucharis, who failed miserably despite having a 10,000 to 1 advantage in manpower. He actually managed to lay siege on the Fang but failed to do anything to it (unsurprisingly, given TS needed custom strike cruiser turned into a giant plasma cannon to break through the fortress's void shields), until the companies, who where stationed on their ships when his fleet arrived made a planetfall behind his army and sandwiched it between themselves and the defenders of the Fang, massacring it to a man.
• Finally it was invaded by combined force of Ordo Malleus, Grey Knights and a Space Marine chapter during which immense badassery ensued as Logan Grimnar 1) Killed a Grandmaster and some Justicars and 2) Killed the Inquisitor trying to fuck with him. Bjorn the Fell Handed convinced him to negotiate a cease fire because there was more cheese than his space furries could handle. Since then the Inquisition has avoided Fenris.

All three times the harsh environment of Fenris scored more kills than the Space Wolves, which is something to say when you are competing with more than a thousand viking superhuman killing machines.

Round 4 aka Yiff in Hell

Recently Fenris has been attacked again by Chaos forces and GW has really made it clear things are going bad for them, with the Dark Angels severely damaging at least one planet in the system, Midgardia.

Then Magnus the Red, Daemon Primarch of Tzeentch shows up. Yeah, things are going really well for the Wolves.

Magnus succeeds at wiping pretty much all life on Fenris in the most disturbing and cruel way, but ultimately gets banished for his trouble. Then the Inquisition and Grey Knights proceed to wipe the those countless thousands of surviving Fenrisians who had fought against the daemon incursion, because now they're tainted by Chaos, unfortunately this time Wolves have not enough strength to stop them. It also meant having to open their doors to the Inquisition; and now the Ordo Hereticus are frequent visitors, no doubt using the conflict as an excuse to get their foot in the door and keep tabs on the chapter.

In the aftermath though, the Rune Priests proclaim that the spirit of the World Wolf is whole once more, yet new, more terrifying monsters would stalk the wilderness and give the Fenrisians (who already dealt with Krakens and Werewolves) something new to deal with.

The other planetary bodies of the system were also significantly damaged:

Midgardia was infested by Nurgle and was subjected to two exterminatus, first by the Dark Angels, then by the Wolves themselves, absolutely obliterating it, causing meteor showers all across the system. Bringing wasting illnesses with them wherever they impact on other planets.

Svellgard was once an ocean world, but Midgardia's destruction caused solar flares which boiled away the water, leaving it a glassy, salty desert planet.

Frostheim had it's ice melted away by warpfire induced by the Alpha Legion, leaving a thick layer of prehistoric bone that was said to come to life and hunt for the blood of the living under the sign of the new moon.

Fenris' own moon Valdrmani was rendered into a hellish wasteland, but was reconsecrated and rebuilt into an astropathic relay station.

So Wolves may now be living on borrowed time. The world had a population of less than 3,400,000 before the war broke out, now undoubtedly reduced following the planetary invasion and subsequent purging by Grey Knights. Coupled with the revelation that exposure to the Wulfen Curse is contagious, seeming to accelerate it's eruption in other Space Wolves, it may mean the chapter doomed to either die out, mutate into wulfen, or lose their sanity and turn to Chaos like the Wolf Brothers before. Either that or the chapter has to adapt and turn into something else entirely.

If only they had that cure Strawberry destroyed the first time he attacked... At least the space yiffs would get their chance to go down in a blaze of glory, seeing as the 13th Black Crusade starts pretty much immediately after the 4th battle for Fenris.

If you look at where the great rift is on the 8th ed teaser map it looks like Fenris would be smack bang in the middle of it...looks like all that wolfing has caught up with the wolf wolves