I've tried the arena fights and have made it to Champion, where the next step is to challenge the Grand Champion, the "Gray Prince". However, since I made his quest earlier, finding out the truth about his parents, he doesn't fight back in the arena. He just stands there saying "Please, kill me..." and there is no way to reason with him, the conversation ends directly after he says his piece.
If I kill him in that match, without him fighting back, it is treated as a Murder, despite it being in a deathmatch in an arena made for deathmatches. However if I attempt to spare him and abort the match I am unable to exit the arena, since the door says I must slay my opponent first.
Do anyone have any advice on how to solve this quest? I do not want my character to be written up for murder just to be able to continue playing.