Demons aren't really known for their composure and restraint. In fact, it's sort of one of their hallmarks that they don't have composure and restrain, for the most part. As such, calling a set Rage of Demons seems rather fitting. Since I don't think "Tolerance of the Demons" or "Quiet Contemplation of the Demons" would've gone over so well.
Each booster pack for Rage of Demons contains 1 large figure and 3 small or medium figures. This set has such iconic monsters as the Beholder, Djinn, Nightmare, Rust Monster (personally really hate those guys), Roper (no Ebert), and more. You can see a full list, with photos, over on the announcement page.