Ravnica block
The Ravnica block is comprised of thee sets: Ravnica: City of Guilds (File:Ravnica.gif), Guildpact (File:Guildpact.gif) and Dissension (File:Dissension.gif).
The Ravnica block centered around exploring multicolor cards and concepts in depth, and as such was a spiritual successor to the Invasion block. It was the first block to introduce the "guild model". Where older blocks showed an evolution of the abilities and/or keywords such that the newest set was more advanced (complicated), the guild model contains a number of guilds that are evolved as much as they are going to be, until another block touches on the guilds again.
The Ravnica block featured the following keywords: Bloodthirst, Convoke, Dredge, Forecast, Graft, Haunt, Hellbent, Radiance, Replicate, and Transmute.
This block is the first to feature "hybrid mana."
Mega Cycles
Ten mega cycles existed across the three sets, each made up of ten cards, one for each guild:
- Dual-color guild masters: Grand Arbiter Augustin IV, Teysa, Orzhov Scion, Agrus Kos, Wojek Veteran, Tolsimir Wolfblood, Circu, Dimir Lobotomist, Tibor and Lumia, Momir Vig, Simic Visionary, Lyzolda the Blood Witch, Savra, Queen of the Golgari, and Ulasht, the Hate Seed — These legendary multicolor creatures, one for each two-color pair, and each of which cost a certain amount of colorless mana plus one mana each of their respective colors, rewarded players for playing with cards of their two colors, often doubly so for using multicolor cards. For instance, Augustin reduced the cost of white spells and blue spells by
, and multicolor white/blue cards by 
. - Utility guild masters: Isperia the Inscrutable, Ghost Council of Orzhova, Razia, Boros Archangel, Chorus of the Conclave, Szadek, Lord of Secrets, Niv-Mizzet, the Firemind, Experiment Kraj, Rakdos the Defiler, Sisters of Stone Death, and Borborygmos — These legendary multicolor creatures, one for each two-color pair, and each of which cost a certain amount of colorless mana plus two mana each of their respective colors, produced powerful effects thematically tied to their respective colors. For instance, Niv-Mizzet allows for both card-drawing (a blue trait) and direct damage (a red trait).
- Guildmages: Azorius Guildmage, Orzhov Guildmage, Boros Guildmage, Selesnya Guildmage, Dimir Guildmage, Izzet Guildmage, Simic Guildmage, Rakdos Guildmage, Golgari Guildmage, and Gruul Guildmage — Each of these uncommon 2/2 creatures costs two hybrid mana of its guild's colors. Each has two activated abilities relating to its guild's colors. For instance, Simic Guildmage can move auras from one creature to another (a blue ability) and +1/+1 counters from one creature to another (a green ability).
- Common Hybrid Spells: Minister of Impediments, Mourning Thrull, Boros Recruit, Centaur Safeguard, Lurking Informant, Petraydrox, Shielding Plax, Riot Spikes, Gaze of the Gorgon, and Wild Cantor — Each of these common spells have hybrid mana costs.
- Rare Hybrid Spells: Dovescape, Debtor's Knell, Master Warcraft, Priveleged Position, Shadow of Doubt, Djinn Illuminatus, Biomantic Mastery, Avatar of Discord, Gleancrawler, and Giant Solifuge — Each of these rare spells have hybrid mana costs.
- Guild Artifacts: Walking Archive, Moratorium Stone, Sunforger, Crown of Convergence, Bloodletter Quill, Mizzium Transreliquat, Evolution Vat, Rakdos Riteknife, Plague Boiler, and Gruul War Plow — Each of these rare artifacts had an activated ability thematically linked to its guild with a cost including one mana of each of its guild's colors.
- Signets: Azorius Signet, Orzhov Signet, Boros Signet, Selesnya Signet, Dimir Signet, Izzet Signet, Simic Signet, Rakdos Signet, Golgari Signet, and Gruul Signet — Each of these common artifacts has ",
: Add (one mana each of the respective guild's color) to your mana pool." - Bounce Lands: Azorius Chancery, Orzhov Basilica, Boros Garrison, Selesnya Sanctuary, Dimir Aqueduct, Izzet Boilerworks, Simic Growth Chamber, Rakdos Carnarium, Golgari Rot Farm, and Gruul Turf — Each of these common lands has "This card comes into play tapped. When this card comes into play, return a land you control to its owner's hand." Each could be tapped for one mana each of the appropriate colors. Each was illustrated by John Avon.
- Guild Lands: Prahv, Spires of Order, Orzhova, the Church of Deals, Sunhome, Fortress of the Legion, Vitu-Ghazi, the City-Tree, Duskmantle, House of Shadow, Nivix, Aerie of the Firemind, Novijen, Heart of Progress, Rix Maadi, Dungeon Palace, Svogthos, the Restless Tomb, and Skarrg, the Rage Pits — Each of these uncommon lands, representing the headquarters of each of Ravnica's guilds, could be tapped for . Each also had an activated ability whose cost included one mana of each of its guild's respective colors, tied to each guild's theme. For instance, Vitu-Ghazi could produce saproling tokens, which was beneficial to the Selesnya Conclave's Convoke ability. Each was illustrated by Martina Pilcerova.
- Shocklands: Hallowed Fountain, Godless Shrine, Sacred Foundry, Temple Garden, Watery Grave, Steam Vents, Breeding Pool, Blood Crypt, Overgrown Tomb, and Stomping Ground — Each of these rare dual lands had two basic land types, could be tapped for two colors of mana, and came into play tapped unless its controller payed 2 life. Each was illustrated by Rob Alexander.
