Yup, he represents a big step up in difficulty. I beat him last night after about 6 attempts. You pretty much have to try and get through the first phase without using too many of your cooldowns so you can blitz him down with them in the 2nd phase. Make sure you have enough points in staff skills to unlock the second focus point. I switched my spirit to the Wandering Wight as that passively increases your defense plus using his ability deals a ton of damage. I also relied heavily on the transformation and used the immobilise spell every time it came off cooldown. Also, after beating him I wondered if investing points in thrust stance may have been useful particularly for the first phase where he frequently stands back and doesn't engage. The thrust stance allows you to attack enemies at distance.
