A Remix Heart(リミックスハートRimikkusu Hāto) is a unification of a Human and a Grimoire seen in BlazBlue: Remix Heart. Mai Natsume is the only known Remix Heart, as she is a human vessel of the Nameless Grimoire, and, for a time, the Intermediary Grimoire. A Remix Heart is required to smelt the Crimson Grimoire, which was researched by Seifer Albar.