Orcus, god of undeath, creates ghasts by infusing ghouls with a particularly baleful dosage of his abyssal energy. Whereas a ghoul is little more than a savage beast, a ghast is cunning and can inspire a pack of ghouls to obey its commands.
Ghasts are similar to Ghouls – sharing a hunched, lean appearance and paralysing claw attack – though larger, stronger, and permanently bearing an aura that resists being turned. They also have the unique ability to weaponise their stench and cause nausea in foes.