Orcus does physical damage and some spell damage, both of which you should be ready for. He also carries a wand of death, although for any character with magic resistance, the main problem this poses is how to relieve him of it without him wasting too many charges (hint: wield a cockatrice corpse)
Orcus, Prince of the Undead, has a ram's head and a poison
stinger. He is most feared, though, for his powerful magic
abilities. His wand causes death to those he chooses.