I know he is easy but such a long fight and it's just very likely to mess up once and boom over. Therefore, just do him in NG+, you will have 5 giant souls then. I was doing over 1k damage per L2 with dual old whips
Darklurker: don't even read on if you aren't interested in cheesing him
Again, pretty weak to fire and a lot of folks don't find him that tough. Others do. And the run up to him is evil and costs an effigy a pop. So, casting profound still doesnt shut him up completely but costs him his only ohk attack, that dark aoe in front of him, he tries to cast it but to no avail. So now you have the chance to cast chaos storm. Heal and repeat.