Dirge of Cerberus: Final Fantasy VII
Voice Actor: Bob Joles
Grimoire Valentine was a very successful scientist who worked for ShinRa alongside some of their other top professionals. His involvement in Dirge of Cerberus happens during his time working with Lucrecia Crescent - specifically when they're working on research to do with both Chaos and Omega Weapon.
Grimoire was one of the few scientists in ShinRa who actually believe Lucrecia's theories and decided to help her with her research. However, when an experiment went wrong, there was a terrible explosion and Grimoire died saving Lucrecia's life.
It was this incident that made Lucrecia distance herself from Grimoire's son, Vincent, as she felt she was responsible for Grimoire's death.
The Creation Of Nero The Sable
Prior to working alongside Lucrecia, Grimoire gained a reputation due to his research about life being created by stagnation of Lifestream. This discovery saw lots of research take place by injecting stagnation into live subjects - mainly unborn children.
The experiment was performed in hundreds of fetuses, but only one experiment was successful - Nero. While giving birth to Nero, his mother was absorbed into the Darkness that he emitted.