This post is five years old and the other people are probably long gone.

Also I have to point out, your instructions aren't really "how to win without fighting the boss". That is simply what you are expected to do to complete the duty. The Ascian isn't the boss to be fought; he's just there as set dressing for your fight against the summons and effort to attune to the aether.

If something is that tough, you're probably not supposed to be fighting it at all.