Jack Black as Jack "Jables / JB '' Black Troy Gentile as young JB Kyle Gass as Kyle "Kage / KG '' Gass JR Reed as Lee Ronnie James Dio as himself Dave Grohl as Satan Ben Stiller as Guitar Center Guy Paul F. Tompkins as Open Mic Host Tim Robbins as The Stranger John C. Reilly as Sasquatch Meat Loaf as Bud Black Cynthia Ettinger as Betty Black Andrew Caldwell as Billy Black Amy Poehler as Truck Stop Waitress Colin Hanks as Drunk Frat Dude Amy Adams as Gorgeous Woman Gregg Turkington as Stand Up Comic (credited as Neil Hamburger) Evie Peck as KG 's Mother Jason Segel as Frat Boy # 1 David Krumholtz as Frat Boy # 2 Fred Armisen as Security Guard # 1 Ned Bellamy as Security Guard # 2 Jay Johnston as Gang Member # 1 John Ennis as Gang Member # 2 David Koechner as Surplus Store Clerk (deleted scene)
who played the devil in tenacious d movie
Dave Grohl