What is "d'hoffryn"

D'Hoffryn is a fictional character on Buffy the Vampire Slayer, played by Andy Umberger. He is a powerful entity high in the demonic hierarchy. He's the master of the vengeance demons, a cabal which includes humans who are "elevated" to demonic status and endowed with mystical powers enabling them to invoke revenge at the behest of mortals who believe they have been wronged. D'Hoffryn rules over a hell dimension known as Arashmahaar.