Ravnica

The city-plane of Ravnica is populated by ten immensely powerful guilds that simultaneously must work in harmony and compete for dominance. This structure backed by the binding magical laws of the Guildpact created a system destined to collapse, which was exploited by the planeswalker Nicol Bolas for his own dreams of returning to godhood. The devastating War of the Spark that followed would push the plane to the brink, although the mad Dragon planeswalker was thwarted. Now, the guilds under the leadership of a new living Guildpact are attempting to rebuild all that was lost in the carnage.