Class Tipid chose on re-entering the dungeon, which he calls a good one and which grants Murder Tornado.
Liquid Dervish is the class Tipid selected when he checked in under The Standard Merc Package, and it appears in his name plate: Tipid, Crest Liquid Dervish, Level 60, Colonel in The Princess Posse. During his original crawl he ran a poisoner class and reached level 96; on returning he traded it for this, and he grins when he calls it "a good one."
The class supplies him at minimum the Murder Tornado spell, which he prefers to any pulse rifle the enemy Hired Mercenary troops carry — an important consideration, since the merc package hands out no gear at all.
Tipid's returning class, evidently spell-heavy enough to compensate for having no equipment.