Ascending at low level

If I am a low lvl Mo/N 13, will the doppledanger be lvl 20? even though tis a mirrior of me?

i believe so, but that doesn't matter your half necro. latch on divine boon to self heal(he won't) and the rest life sacrafice. he'll eventually kill himself.

i use healing breeze works great, he does not use that skil

other than the fact he will be lvl 20, he will have the best armour available for his class, max attribute points in all his attributes (and i mean all as in attributes of all classes, which explains why his bow and axe attack is deadly), have 480HP and have Bow and axe instead of the measly wand/staff you are using.

i suggest buffing up a little before fighting him...

one skill to help keep you alive is Pacifism, i think its pretty underrated but that is the only reason i survived my mirror, but scince your a necro it may be diffrent.. anyways good luck

on a side note : it's not a mirror, it's a doppleganger
which means it's only copying you

this is what you neeed, healing breeze, he cant use it, and a sacrafice skill. let him use the sacrifice skill, while you just use healing breeze and he will kill himself.