Nightmare beings from the negative material planes that have a hierarchy of evil. They are bent on the destruction of all that is good, domination, corruption, and perversion of the multiverse and the subjugation of all other beings.
Some daemons of note:
Orzalon is a general in the conflict known as the EverWar, waged for eons between the forces of light and law, chaos and darkness, good and evil. Orzalon intends to use Osterra as a staging ground for further expansion into the multiverse, since it connects to many other realms. He has sent his minions to prepare the way and spread The Corruption.
Sicarius The Red is an insidious deamon. A malevolent force that takes possession of his victims, working his evil plots forward and leaving a wake of ruined lives.
They have enslaved multiple worlds including the Orc's home world. They can corrupt other’s and enslave their minds. Those who have been corrupted might also be able to infect others. Their first goals are to control the portals and wipe out resistance.