The Demon Revolution was a series of revolts led by the demon Grendel, when fighting against the demon Ramuthra roughly twenty years before Stórrekkr the Great was born and ending some five years before Stórrekr expulsed the demons into the Other Place. It's main members were the demoniac entity Grendel, and most demon-aligned angels (the angels located in our world), especially Angel Israfel, entity destroyed during the revolt.