Manthei began his game writing career working on titles such as Panzer General II, Vampire: The Masquerade - Redemption, Sacrifice, Wizardry 8, Twisted Metal: Black.
Manthei's early work involved creating content for various popular video games, including titles like Panzer General II, Vampire: The Masquerade - Redemption, Sacrifice, Wizardry 8, and Twisted Metal: Black.