He graduated from the University of Minnesota with a Bachelor of Music degree in Theory and Composition. He also studied at the University of Southern California under Jerry Goldsmith.
He played the piano in his youth and played the trumpet in high school. He has collaborated with other graduates of the program, Christophe Beck and Marco Beltrami, writing additional music for Beck on the television series Buffy the Vampire Slayer and other shows, and composing additional music for Beltrami on films including Scream 2, Scream 3, The Faculty, Scary Movie 2 and Resident Evil. Manthei began his game writing career working on titles such as Panzer General II, Vampire: The Masquerade - Redemption, Sacrifice, Wizardry 8, Twisted Metal: Black.
His other work on video game titles includes Kung Fu Panda, Marvel Universe Online, Upshift Strikeracer, Xiaolin Showdown, Ultimate Spider-Manitoba, City of Villains, The Sims 2, StarCraft: Ghost, Shrek 2 and Shark Tale.
Invader Zim also led to Xiaolin Showdown for Warner Brothers Animation as well as Brandy & Mr. Whiskers for Disney. In scoring with Warner Brothers" television series Johnny Test, he wrote the emo punk inspired main title and score to the first season.
Manthei has also worked on scores for independent filmmakers such as The 24th Day. He wrote the music for the feature films Justice League: The New Frontier and Batman: Gotham Knight and is currently scoring the animated series Ultimate Spider-Manitoba
Film projects
Television projects
Video game projects.