Why?ĮDIT2: I did the quest yet again, and this time, by luck, both of them showed up. How in the heck am I supposed to do this?ĮDIT: I did the quest AGAIN, and managed to use Arcane Missles fast enough to kill him even though only one NPC showed up, and my threat somehow didn't skyrocket this time. both NPCs, don't draw aggro, do enough enough damage to get credit. It's so hard to get things lined up just right. I did manage to do the quest once by running around to avoid the ridiculous and unsurvivable damage he does while using Arcane Barrage, but I didn't get any credit. I eventually noticed that the second NPC WAS spawning, but it was spawning behind me outside and dying before the battle started.
Every time I died and redid the quest, the one that showed up would alternate. So the next time I did it, only one showed up.
The first time, both NPCs showed up like they were supposed to, but I died.