Kroggareth

This mighty Abyssal fiend has a man's massive body, 8 1/2 feet tall and 3 feet wide, in blackish-green leathery hide, topped by a crocodile's head with black antlers. His eyes are pure red, his many teeth sooty black, and his 5-foot tail ends in a yellowed ivory stinger.

With 19 Strength (+3 hit, +7 damage) his claws deal 2-8 each plus the bonus, or he may wield a weapon instead. If both claws land, bite (2-12) and sting (3) hit automatically, and the sting has a 45% chance to drain a level, giving him the lost hit points (by the victim's class die) up to his original total.

As a 20th-level caster he has at will: fly, infravision, dispel magic, know alignment, detect invisible, detect magic, darkness 10' radius. Thrice daily: teleport, suggestion, shout, invisibility, plane shift, polymorph self. Daily: chaos, or gate 2-4 buzzing demons (45%). Weekly: forcecage, mass charm. He also uses wizard scrolls.

His saves are the better of a 16th-level wizard's or fighter's. At a quarter of his hit points he flees by plane shift or any other means. He holds grudges, and if slain he re-forms on his home plane a year later to torment his killers.