Just for fun I went to the Arena for the first time, killed e opponents and was fighting the fourth, Garenor a dwarf, he summoned a Pit Fiend and I killed it but Garenor has dissapeared so now I just stand in the pit waiting....:/
It's probably some random thing?
Reload earlier save.
You lose nice items if you go so late in the game.
After day 5 you become "Ultimate Fighter".
Update:
Are you fighting mage or fighter duel?
Edited by micbaldur, 04 January 2013 - 09:11 AM.