This made me laugh so much! I love how he just straight-up ignored you love your use of the arrow of ill matter to stop him from regenerating that's genius! I'll be using that with my rogue build. THANK YOUUUUU!
Well that was odd, he usually wants to fight. Maybe because you were alone? Maybe, did you rescue the amulet monk yet? I can't think of anything else that might or might not trigger it.