Grimoire Heart

Grimoire Heart (グリモアハート Gurimoa Hāto 悪魔の心臓lit. Demon's Heart) is one of the top three Dark Guilds that the Balam Alliance is comprised of, as well as the one commonly considered the strongest Dark Guild. The guild owes its name to the Devil's Heart,an organic device which is the source of Guild Master, Hades' immense power, kept inside the guild's airship.