Quest "Amphitheater of Anguish: Magnataur!" cannot be completed (sometimes) because killing the required NPC does not fulfill the quest requirement and cannot be turned in.
While the arena questgiver NPCs are a bit buggy when others are also doing arena quests, I tried dropping the quest and picking it back up later and still could not complete the quest.
Also, "Amphitheater of Anguish: Yggdras!" is offered twice by the questgiver.
Edit: after a few times later on it completed, but there is still definitely something screwy with quest completion.
Quest "Amphitheater of Anguish: Magnataur!" cannot be completed (sometimes) because killing the required NPC does not fulfill the quest requirement and cannot be turned in.
While the arena questgiver NPCs are a bit buggy when others are also doing arena quests, I tried dropping the quest and picking it back up later and still could not complete the quest.
Also, "Amphitheater of Anguish: Yggdras!" is offered twice by the questgiver.
Edit: after a few times later on it completed, but there is still definitely something screwy with quest completion.