Guest Stars Steve Alterman voices Additional Voices Mae Whitman voices Heather Mitch Carter voices Additional Voices David Faustino voices Dagur Nolan North voices Stoick Haddock JB Blanc voices Ryker Chris Edgerly voices Gobber Alfred Molina voices Viggo Grimborn Alan Shearman voices Additional Voices David Tennant voices Spitelout Jorgenson Adelaide Kane voices Mala James Arnold Taylor voices Throk Julie Falls voices Additional Voices Lucas Grabeel voices Gustav Larsen Warren Sroka voices Additional Voices