From publisher blurb: The Archmage BANISHES them. The Crusader CONQUERS them. The Great Gold Wyrm DEFIES them. The Diabolist SUMMONS them. When the world cracks open and the demons attack, what will YOU do? The Book of Demons takes an in-depth look at the Abyssal enemies of the 13th Age — the demonic hordes whose eternal struggle to shatter reality causes hellholes, dimensional breaches, and other, even weirder assaults on the world. For Players: A new demonologist PC class, with three paths: corruption, flame, and slaughter! For Game Masters: Six detailed hellholes and their denizens, plus advice on making your own A new random demon abilities table Citadels of the Crusader and the Diabolist Monster stats for nine new demons summonable by player character demonologists