Use flaming boomerangs targeting the arms, legs and chest to eventually burn off his fur to reveal the true form. Meantime, keep moving to dodge the fists.
Once the fur is burned off use the flame boomerangs on the oil fires that occasionally spring up- this will do damage. After about 5 hits he should melt into the snow. In the cutscene that follows you'll meet his final form. Use Frostyrangs on the flaming funnel on his head to finish things off.