It’s important I tell you I came back to this area after chapter 2. So I was level 30 and smacked this guy around like he was nothing. So if you are stuck, just keep in mind you can come back to him. If you don’t already have it, go and kill the Wandering Wight. You will collect an his soul ability that could come in very useful for this fight.
If you don’t want to wait, I’ll do my best to help you out here. Use body-cooling powder to help heal the fire damage he causes. Evil repelling medicament can really help with defense if you’ve managed to collect any.

Watch out for long distance strikes as he will sweep across the map a couple times and follow it up with a melee combo.
If you are up close and personal, stay on top of dodging his never ending swings. Once your sure he has stopped, start swinging then. If you’ve unlocked the ability to freeze your enemy, be sure to do so here.
If you are struggling, I always recommend going in with no intention of winning, just see how long you can survive by just dodging so you can learn his attack patterns and get acquainted with dodge timing.