Ravnica

"A perpetual haze of dreary rain hangs over the spires of Ravnica. Bundled against the weather, the cosmopolitan citizens in all their fantastic diversity go about their daily business in bustling markets and shadowy back alleys. Through it all, ten guilds--crime syndicates, scientific institutions, church hierarchies, military forces, judicial courts, buzzing swarms, and rampaging gangs--vie for power, wealth, and influence. These guilds are the foundation of power on Ravnica. They have existed for millennia, and each one has its own identity and civic function, its own diverse collection of races and creatures, and its own distinct subculture. Their history is a web of wars, intrigue, and political machinations as they have vied for control of the plane."

– WotC's description of Ravnica in its D&D 5e splatbook.

Ravnica is a plane in the universe of Magic: The Gathering. It's essentially a giant city (in fact, its tagline is "City of Guilds"), continuously expanding outward and upward (rather like the hives of Warhammer 40,000). It is vaguely Eastern-European in flavor, with Russian, Polish, Hungarian, Serbian and Croatian influences on its design, names, and phonetics of its made-up words. When someone says a deck is a [part of guild name] deck, that might only mean the deck's colors is the same colors as that guild, e.g. any black-green deck can be called a golgari deck.

Guilds

Ravnica is run by ten guilds, each of which embodies two of Magic's colors:

The Azorius Senate

White and Blue. Boros may be THE LAW, but the Azorius Senate is the legislature and court system. They are known for being extraordinarily stuffy, unproductive, and beaurocratic.

The Orzhov Syndicate

White and Black. They act like a church, but they're really all about the money and function as a debt-collecting, guilt-inducing mafia. Their power is both in holiness, and shadow, and extends beyond death. Beware a contract with them. In short, think Supernatural version of the Mafia, who revel in making offers you can't refuse.

House Dimir

Blue and Black. The guild of spies and the literal guild of Just as planned (one of their stated functions is to undermine the Guildpact to tease out errors, which some military people might liken to aggressor squadrons), so secretive that its very existence was considered a myth until a big storyline reveal. Their purpose in shadows is sometimes served too well, as after the fall of the Guildpact, and during the rise of its replacement, they have schemed against the greater good and nearly destroyed much of Ravnica in Dragon Maze. All for the possibility of being the last guild standing unopposed. their also secretly the most powerful guild in all of ravnica

The Izzet League

Blue and Red. Mad scientists, wizards, and inventors, ruled by the dragon Niv-Mizzet. They're a little fuzzy on the idea of "safety", while also being tasked with maintaining and improving the city's infrastructure. When asked how much power is required, Izzet mages always answer "More". This leads to Dwarf Fortress style FUN.

The Cult of Rakdos

Black and Red. They're a Chaotic Evil pleasure cult/carnival/assassins guild that other guilds keep around for cleaning up loose ends, and because they would be just that painful to remove, not that some aren't trying. The Rakdos value showmanship, acknowledge that life is short, and specialize in shortening it more for a bloody show.

The Golgari Swarm

Black and Green. Bugs, critters, moss, and zombies, zombies everywhere. Functions as the waste management guild. Was given one of the most broken keyword mechanics in any cardgame, then a dud one. They are mostly sewer-dwelling, and frequently pessimistic.

The Gruul Clans

Red and Green. Formerly in charge of keeping Ravnica connected to nature, the Gruul are not so much a unified faction as a bunch of clans of Chaotic Neutral anarchists. They were formally in charge of Parks and Recreation. Really. The Gruul are mostly in favor of tearing down the structures and the city in general, returning to the wild nature that they revere.

The Boros Legion

Red and White. THEY ARE THE LAW! Law itself is more of Azorius domain however, the Boros are more concerned with what they believe to be justice. They are the military of Ravnica, and are unparalleled in tactics, if lacking in vision.

The Selesnya Conclave

Green and White. A nature cult that brainwashes people who join it. Note: not a cult like that of Rakdos, more in the hippie sense. Selesnyans value unity in all things, though not much diversity. They, not the church Orzhova, are the most spiritual on Ravnica.

The Simic Combine

Green and Blue. Genetic engineers who now dabble in holistic methods. Like Selesnya and (formerly) the Gruul, the Combine maintains what remains of nature on Ravnica, but instead of letting nature take its course, they adapt it to fit with industry and civilization.

Guildmasters

Each guild of Ravnica has a leader, some of whom are the original founders, or Paruns, of the guild.

The Azorius Senate

Founded by Azor, about whom little is known to the fan community, but has been confirmed to not be from Ravnica originally. Formerly led by the sphinx Isperia, who then got turned to stone by Vraska. Dovin Baan is now leading the Azorious.

The Orzhov Syndicate

The Orzhov are led by a council of ghosts known as the Obzedat. Who this comprises is mostly unknown, and current members may include some of the original signers of the guildpact.

House Dimir

Founded by Szadek, a vampire. Currently led by Lazav, a shapeshifter.

The Izzet League

Founded and continuously led by the great dragon Niv-Mizzet, for whom it is named. In recent developments, Niv has disappeared and Ral Zarek has taken over for the time being.

The Cult of Rakdos

Founded and continuously led by the cruel and chaotic demon Rakdos, who gave it its title.

The Golgari Swarm

Founded by Svogthir, a human lich, and currently led by Jarad, an elf lich. This guild has an abnormally high turnover rate for its leadership positions, for which being technically dead does not disqualify you. Notably, Jarad became a lich because when he died in the first Ravnica's story, his spirit quickly returned to the scene and possessed his own corpse. Jarad can't seem to catch a break, and got petrified by Vraska who has taken over as leader.

The Gruul Clans

Founded, per se, by the cyclops Cisarzim. Currently unofficially led by the cyclops Borborygmos.

The Boros Legion

Founded by the angel Razia, Currently let to war by the more direct angel Aurelia.

The Selesnya Conclave

Founded by Mat'Selesnya, currently led by Trostani, each multiple dryads made one.

The Simic Combine

Founded by an unknown person with the name "Simic", currently led by the merfolk Zegana.

Guilds of Ravnica
Azorius Senate	Orzhov Syndicate	House Dimir	Izzet League	Cult of Rakdos
Golgari Swarm	Gruul Clans	Boros Legion	Selesnya Conclave	Simic Combine

Native Races

As a dungeonpunk fantasy Ecumenopolis (that's the fancy word for "city planet"), Ravnica is home to a vast array of races, who have been forced to learn to get along as the city streets swallowed up the wild places and the dungeons, forcing people to learn to get along. There's never been a proper "official list" given out by WotC, but looking at the cards and the setting fiction presents the following native races:

Humans: Because every setting has to have humans, right?

Elves: Divided into three different tribes, each associated with a specific guild. The Silhana are the traditional "wood elves"; nature worshippers who embrace Green Mana, who have become synonymous with the Selesnya Conclave. The Devkarin are Ravnica's "dark elves", being a reclusive tribe of elven necromancers who embrace Black Mana, and thus have intertwined themselves with the Golgari Swarm. The final tribe has lost its original name, but its embrace of Blue Mana makes them Ravnica's "high elves" and has seen them fall in with the Simic Combine.

Vedalken: Hyper-logical, intelligent, magically adept humanoids, the towering Vedalken are the iconic Blue Mana humanoids of Ravnica, and are found in the Azorius Senate and Simic Combine predominantly, although some mavericks gravitate towards the Izzet League instead.

Centaurs are mostly associated with the Gruul Clans and the Selesnya Conclave.

Minotaurs are predominantly found amongst the Gruul Clans, but they are also known to join the Cult of Rakdos and the Boros Legion.

Goblins have adapted well to Ravnica, mostly by staying in the shadows or falling in with those organizations that value their Red Mana natures (to whit: impulsive, mischievous, emotional, and fond of breaking things, blowing things up, and setting things on fire). They are found amongst all four of the Red Mana guilds; the Gruul Clans, the Cult of Rakdos, the Izzet League, and even the Boros Legion.

Loxodons are towering, gentle-natured humanoid elephants, whose strong sense of community leads them to the ranks of three of the White Mana guilds; the Selesnya Conclave, the Azorius Senate and the Orzhov Syndicate.

Viashino are raptor-like lizardfolk characterized by their whip-like tails, which are tipped in razor-sharp bone blades they use as formidable natural weapons. Red Mana aligned, they naturally gravitate towards a violent lifestyle, courtesy of strong predatory instincts; they gravitate towards the Gruul Clans, but are found in all of the Red Mana guilds.

Angels are embodiments of White Mana associated with the Azorius Senate, the Boros Legion, and the Orzhov Syndicate.

Demons are embodiments of Black Mana exclusively associated with the Cult of Rakdos, though the occasional (possibly illusory) weirdo has been spied skulking around House Dimir.

Giants are predominantly found amongst the Gruul Clans. Two-headed giants are known to inhabit Ravnica, as do Cyclopses - in fact, Cyclopses have been known to work for the Izzet League, equipped with giant-sized Power Armor to make them more useful to the guild. Trolls, by comparison, are exclusively found amongst the Golgari Swarm. Ogres have been known to join the Cult of Rakdos.

Medusas, called Gorgons here, are inhabitants of the Undercity and aligned with the Golgari Swarm.

Elementals consist of two distinct varieties. The Selesnya Conclave houses "pure" elementals of earth, wood and water, whilst the Izzet League creates artificial elementals called "Weirds" by hybridizing different kinds of elemental energy.

Sphinxes are associated with the Azorius Senate.

Undead of the sapient kind are associated with different Black Mana guilds; ghosts with the Orzhov Syndicate, vampires with House Dimir, and revenants and/or liches with the Golgari Swarm.

Merfolk were revealed to have existed in the covered-over seas of Ravnica in 2013, and were responsible for shaking up the Simic Combine to try and bring it back from its modern "evolution-worshipping mad biologist" characterization to its historical "holistic bio-transhumanist" characterization. Cynics have suggested that they were an attempt to compensate for the distinctly lackluster reception to Vedalken, who have never really managed to be too popular as the "Blue Mana Race".

Fey are predominantly associated with the Selesnya Conclave, which is particularly home to Dryads, but a number of fairy-type fey are known to belong to the Izzet League.

Krauls are a race of giant, sapient, vaguely humanoid beetles who are aligned to the Golgari Swarm.

Doppelgangers are reputedly part of House Dimir.

In addition to all of the above, the Simic Combine is known to create its own unique races by splicing together humanoids with animals or other humanoids, or mixing animals together and evolving them to develop human-level intelligence. Given that apprenticeship in the Combine consists of "let your superiors experiment on you and hope you come out of it with a useful graft or mutation instead of dying horribly", many Simic researchers look like beastfolk or mutants.

Djinn pop up from time to time, occasionally affiliated with the Izzet League, but just as often as free agents.

Tabletop

Ravnica was first featured in the card game with the Ravnica block in 2005 and 2006, which was in turn composed of the "City of Guilds", "Guildpact", and "Dissension" sets. The block was accompanied by the "Ravnica Cycle" trilogy of books, one for each set. It has since become one of WotC's favorite settings, and has been revisited more times than any setting other than Dominaria - indeed, it seems to have usurped Dominaria's former place as the "core setting" for Magic: The Gathering. October 2012 saw the "Return to Ravnica" block's release, which spanned into "Gatecrash" (February 2013) and "Dragon's Maze" (in 2013).

Ravnica has also become officialy associated with Dungeons & Dragons as well. After WotC broke the unwritten rule of "no D&D/MtG crossovers" for Dungeons & Dragons 5th Edition, they were delighted by the relatively warm reception to their Plane Shift articles. This culminated in the release in late November 2018 of the official splatbook "Guildmaster's Guide to Ravnica", which adapts the city-plane as an adventuring setting for D&D 5e.

This decision was... controversial, in no small part because of outrage from Planescape fans (who had been expecting an official 5e release after two editions of being shunned) and, to a lesser extent, from Eberron fans (who were angry that, by comparison, their setting just got a glorified Unearthed Arcana that they had to pay for).

After many leaks, debates and teasers, the GGR debuted with the following content:

• A detailed look at the world of Ravnica, in particular fleshing out the 10th District, a region on the city-world that had never been detailed before.
• New backgrounds for each of the 10 Guilds, all of which converted the "Guildmage" lore by adding bonus spells to the spell-list of any caster with that background.
• Integration of the Renown mechanic, to support working for your Guild.
• Guidelines on how to actually run campaigns when your players all want to belong to different Guilds.
• Two new subclasses; the Cleric Domain of Order, and the Circle of Spores Druid.
• Five new races; Centaur, Goblin, Minotaur Simic Combine Hybrid and Vedalken
• Two new spells; Chaos Bolt and Encode Thoughts.
• 17 new magic items based on Ravnica lore.
• Nearly 80 new monsters.

There were, of course, complaints. For example, the racial array was considered distinctly lackluster, considering all of the possibilities that it offered - previous Plane Shifts had given rules for merfolk and vampire PCs, which would have fitted in just fine, many fans were hoping for a medusa race, and viashino had been part of a race playtesting Unearthed Arcana only to be dropped from the actual book. Another complaint is the lack of referencing any material that wasn't in the PHB or Xanathar's Guide to Everything, when, for example, the Undying Warlock would have been a perfect fit for the Golgari Swarm. Oh and some magic items in it are retardedly broken for casters.

But, for what it's worth, it is a solid book, and certainly better than the Sword Coast Adventurer's Guide, WotC's only other dedicated setting book for 5e to this date.

Settings of Magic: The Gathering
Pre-revisionist:	First Magic Sets - First Urza Block - Arabian Nights Legends - Homelands - Ice Age - Mirage
Weatherlight Saga:	Portal Starter Sets - Second Urza Block Tempest Block - Masques Block - Invasion Block
Post-Weatherlight:	Otaria Block - Mirrodin - Kamigawa - Ravnica - Time Spiral
After the Mending:	Lorwyn - Alara - Zendikar - New Phyrexia Innistrad - Return to Ravnica - Theros - Tarkir - Eldraine - Ikoria
Two-Block Paradigm:	Kaladesh - Amonkhet - Ixalan
Post Two-Block Paradigm:	Eldraine - Ikoria - Kaldheim - Strixhaven
Never in a standard set:	Fiora (Where the Conspiracy sets take place) - Kylem (Battlebond)