Tiến sĩ Grimoire Valentine là một nhà khoa học và là cha 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 was the man who worked on the discovery of Chaos and Omega with Lucrecia Crescent. However, he was killed when an experiment during his research went wrong and he shielded Lucrecia from the blast. This is what caused the guilt felt by Lucrecia, causing her to distance herself from Vincent. During the discovery of Chaos and Omega, he and his team stumbled upon a stagnation of Lifestream found onsite. Scientists took this information and took the stagnation and put it into children about to be born. However they did not know how it was going to turn out, and though they did a few hundred experiments, there was only one experiment that was successful — Nero the Sable.
A "grimoire" is a book of spells.