[Endoperez]

You need some kind of a save-or-die spell, though. Soul Slay, Petrify, Charm, something. That, or mages who can cast more AN damage spells than your opponent can stack resistances, and perhaps thugs in the event he does manage to get all resistances: Thunder Strike, Frozen Heart, Incinerate and a thug(s) with high-damage AP weapon would probably be enough.