The content of this page describes the demons as they appear in the Hollideus universe. For the demons in the Kaelicious universe, see "demon (Kaelicious)".

Demons are a race of creatures created by the Fire God. Majority of them live in Earth's Core of Hell, and are bound to one leader known as the Idol of Halloween. The demons usually fight among themselves each year during October, the winner claiming the title as the Idol of Halloween, who is then encouraged to lead the demon horde to Easterland during the trick-or-treating-tradition of Halloween in November.

The Mad King, Alwin the Fist, the Sinful One and Moltenpyre are all pure demons, while Paillan is a rare example of a cross-breed between a demon and an angel.