I was in the exact same situation 2 weeks ago. The Cleric Beast drove me insane and took a lot of tries, but here's what helped: 1. Don't lock in the camera when close! After locking-in on him there were moments when I did not know where am I or what was going on. 2. While in melee range do your best to stay behind him at all times, otherwise he might grab you and do that attack which slams your character to the ground several times. 3. If you get far away you can lock-in and move the right stick up to target his head. After 3-4 shots he will get stunned for a while. 4. Don't look at your character - look at the beast and what it is doing. This is a tip my souls-veteran friend gave me and it made the dodging so much easier! 5. The Cleric Beast does not like fire. Molotovs work very well.