The Apostasy skill teaches members of the Apostate class the art of both summoning and commanding mighty Baalzadeens and lesser daemons. Those with the Apostasy skill also learn to use sentient daeggers. Perhaps the most feared ability of this skill is the one that allows a Baalzadeen to tear the soul from unwilling victims.
Abilities in Apostasy
| Ability | Description |
| Daegger | Call to your side a living, daemonic daegger to aid you. |
| Hunt | Command your daegger to hunt your enemy. |
| Pentagrams | Sketch an infernal pentagram, in blood. |
| Baalzadeen | Summon your beloved Baalzadeen to do your bidding. |
| Taste | Taste the flesh of your Baalzadeen. |
| Rest | Order your Baalzadeen to rest. |
| Armour | Request that your Baalzadeen grant you protection. |
| Horror | Instill great fear into your victim with your demon's aid. |
| Fiend | Summon a daemon fiend to attack an enemy. |
| Scorch | Order your Baalzadeen to melt icewalls. |
| Presences | Locate those in your local area with your Baalzadeen. |
| Mask | Summon dark powers to mask your demonic servitor. |
| Sap | Drain away the mana of a victim with your loving demon. |
| Trace | Command your Baalzadeen to trace the movements of someone. |
| Fortify | Fortify the health of your Baalzadeen with yours. |
| Apathy | Become numb to the crushing pain of existence. |
| Shadowstrike | Use your daegger to strike at the shadow of a victim. |
| Beckon | Your Baalzadeen is an attractive force indeed. |
| Daemonite | Summon forth a small daemonite to annoy your enemies. |
| Strip | Command your demon to strip the defences from someone. |
| Sear | Order your Baalzadeen to sear the flesh of an enemy. |
| Eliminate | Use your daegger to tear the beating heart from a victim. |
| Bloodworms | Summon forth a horde of these foul lesser daemons. |
| Blast | Order your Baalzadeen to blast your enemies from the room. |
| Mindread | Command your demon to listen to incoming tells. |
| Nightmare | A daemonite born of the rape of the Goddess of Dreams. |
| Fury | Cause those around you to go into an enhancing fury. |
| Stain | Stain the soul of someone with your Baalzadeen. |
| Syphon | Order your Baalzadeen to draw afflictions away from you. |
| Refuge | Seek refuge in the Inferno. |
| Catharsis | Perhaps their death is the greatest mercy there is. |