Grimoire Weiss is a snooty magical tome which like Grimoire Noir uses magical spells through ‘words’ and as well as accompanying and helping Nier serves as his source of magic. He is a mysterious book of great power that contains only a small portion of the sealed verses. Grimoire Weiss hates having his name abbreviated to just ‘Weiss’ and is quick to remind everyone that he is to be addressed by his full name, although later admits he’s grown fond of just ‘Weiss’. Additionally he becomes infuriated when called by titles such as book, weissy, and floating magazine.
Possessing a sharp tongue and inflated ego he’ll often feign ignorance but whether this is done to test Nier or out of pure loss of interest in the subject is unknown. Grimoire Weiss dose not get along with Kainé whom he addresses as the ‘Hussy’ and the two routinely argue. He is most involved in Nier’s quest to cure Yonah of the ‘Black Scrawl’ and unlocks many hidden memories along the way. Despite what he knows and what the forgotten memories reveal Weiss remains loyal to Nier, even going so far as to sacrifice himself.
Weiss is the Gestalt of a Hamelin Organization Crusader (a group of child soldiers raised to use magic to fight against the legions created by the ‘White Chlorination Syndrome’ that spread from the Grotesqueries Queen) that was bound into a book. The true purpose of Grimoire Weiss was to fuse with Grimoire Noir to force the Gestalts (Shades) to return into their Replicant bodies and become true humans again. Although he is repulsed by the idea when Grimoire Noir expresses his desire fuse.