Filgor Orcthane I believe his is name turns invulnerable after getting down to 1/4 health. I am a Bow using Nightblade. This fight isn't really too difficult because I can use scatter shot to keep him away from me, and I was able to kill the spirits healling him, but he was still invulnerable after I dispached the spirits. I am thinking this has to be a bug because unless I am missing something you can't kill someone who doesn't take any damage. I could literally stand there knocking him back and shoot him and see his health bar say the same. I moved in using shadow cloak + veiled strike followed by the assasination ultimate.... still no damage. If something else needs to be done beside killing the two spirits, there really isn't any indication of what is keeping him alive.

Please advise.