Spoilers: Unkillable boss

[Akhanoth]

I am having a lot of trouble with defeating Bleden Mark. At one point during the fight, he simply becomes invisible, and doesn't leave this state. Even if I simply AoE the square where he is, he doesn't dire even after 5 minutes of bursting at him. I have tried killing him several times, but it always ends with him going perma-invisible.

Am I missing something, or is this bugged?

 

[Folkrom]

maybe you got bugged? have you tried reloading a different earlier save?
i have just finished the game and bleden mark ate the dust quite quickly for me (i was level 15) dare i say almost too quickly?

 

[bennibb]

Happend to me aswel... Had to reload (autosafe before the fight) And then I ignored the shadows he spanwed and went full frontal assault. Seems like he doesnt go the eternal shadow mode if you do it like that. But cant realy tell if hes bugged or not since I only played once.