First Moder fight I raised and leveled the ground around the altar (wolves couldn't join in the fight), I had a golem in a pit near the altar (I figured drakes and maybe moder would go after it...not so much), I even raised some pillars to hide behind when needed (great for spit from the air but the breath goes right through)... ran out of arrows, and couldn't get out of the way from the on ground breath.

New game I have draugyr fang fully upgraded, hunters bow as backup, as many poison arrows as I can carry, food, mead, frost resist (might not stack but a frosty one before the fight works), and I dug out eh area under Moders altar as much as I could, battle area became a pit where I could hide behind/under something that wouldn't break (altar). Only got hit by the breath once.