-Sold as a set- (Vol. 1) Monster High ghoulfriends forever Paperback (Vol. 2) Monster High just want to have fun Paperback (Vol. 3) Who’s that ghoulfriend? (Hardcover) Ghoulfriends Forever is a brand-new Monster High series, introducing three new monster characters. As new students, the trio must navigate the bewildering array of cute monster boys, established cliques, and monster-rific subjects like Mad Science, G-ogre-phy, and Physical Deaducation.