The Book of the Dead is a unique Necromancer-specific skill mechanic that allows the player to customize the Necromancer’s minions, how minions are deployed, which minions the player can have, and how they behave. The core skills center on three summons: skeleton warriors and mages, and a golem. Each summon has three variants to choose from. And each variant has three modifications: two Upgrades (only one may be active at atime) and Sacrifice, which disables summoning that minion in exchange for conferring a permanent buff to the Necromancer.