A.C. Bradley Creator, Executive Producer Jeffrey Wright The Watcher Voice Karen Gillan Nebula Voice Jude Law Yon-Rogg Voice Michael Rooker Yondu Udonta Voice Seth Green Howard the Duck Voice Taika Waititi Korg Voice Peter Serafinowicz Garthan Saal Voice Julianne Grossman Nova Prime, Irani Rael Voice Fred Tatasciore Groot Voice Brad Winderbaum Executive Producer Kevin Feige Executive Producer Bryan Andrews Executive Producer Victoria Alonso Executive Producer Louis D'Esposito Executive Producer Matthew Chauncey Writer Stephan Franck Director