Spellbook Demonslayers is a roguelite horde survival game inspired by Vampire Survivors and Path of Exile. Slay thousands of demons with powerful magic to protect the Cosmic Library! Choose new spells and upgrades every run to create overpowered builds with each character, and steal the powers of defeated enemies to destroy the demonic horde.

One of the exiled and imprisoned mages of the Cosmic Library has escaped and is now invading with the demonic horde to get their revenge. The teenage sorceress Ashe stands out to stop the invasion and protect the Cosmic Library. Other mages transform into sentient Spellbooks, so that their powers can be used by Ashe.