Is it on purpose that you cannot retreive Nere's head when he was killed by fire and therefore burned up, or is this a bug? I think it should still be possible.
By making his head unobtainable due to lava, the weird side-effect causes the fire too to be counted as a fail trigger for the quest, which it shouldn't be doing.
By making his head unobtainable due to lava, the weird side-effect causes the fire too to be counted as a fail trigger for the quest, which it shouldn't be doing.
It might be that killing with fire replaces the character model with a generic 'burned' one. Sort of like raising a zombie does the same.