Rakdos leads the Cult of Rakdos

Extinction

Rakdos, called His Viciousness by his followers, is the demonic parun and guildmaster of the Cult of Rakdos on Ravnica. He spends most of his time slumbering in a lava pit located in Rix Maadi. He was given the responsibility of a guild by the Guildpact to bind him to a greater purpose, or at the very least keep him busy enough that he would be less of a problem for the other guildmasters.
Lesser members of the guild are known to "lead" the guild in his periods of slumber, though the chaotic nature of the guild means the role is briefly held. Should they survive attempts on their life by fellow guild members, their death is assured should the Defiler wake.