Grimoire Valentine (グリモア・ヴァレンタイン, Gurimoa Varentain?) is a scientist and father of Vincent Valentine who was introduced in Dirge of Cerberus -Final Fantasy VII-. His red ascot was specifically designed to be reminiscent of his son Vincent's red bandanna.
Grimoire worked on the discovery of Chaos and Omega with Lucrecia Crescent, who was his assistant. It is said he found the Cetran tablet, which spoke of Omega and Chaos, and was the one to write the first Omega Reports. He subsequently located the place where Chaos was destined to be born, Lucrecia's Cave, alongside Lucrecia. Grimoire was killed when an experiment during his research went wrong and he shielded Lucrecia from the blast.
The Omega Reports, written majorly by Grimoire, and by Lucrecia, as well, made evident how long their research of Chaos and Omega was. The reports also show the hypothesis Dr. Valentine and his colleagues made during the research, and states that Grimoire was the one to discover the spring where Omega was to be born. Report number 6, written by Lucrecia, says "The doctor believes the crystalline spring contains contaminated deposits of bioplasma that have overflown from the pure Lifestream". The Omega reports also mention and speak about the Protomateria, the materia found in the Crystal Cavern, which is stated by Lucrecia that was found by Dr. Valentine and that it is a materia of one-of-a-kind, created by the Lifestream.
Having been part of the events that lead to Grimoire's death made Lucrecia feel guilty, and she distanced herself from Vincent. During the discovery of Chaos and Omega, Grimoire and his team stumbled upon a stagnation of Lifestream onsite. Scientists took this information and took the stagnation and put it into children about to be born, but they did not know how it was going to turn out; even though they did hundreds of experiments, there was only one experiment that was successful — Nero the Sable.
A grimoire is a book of spells.