Looking at the comments, I'm surprised no one has mentioned the beast cutter. Sure, the beast cutter doesn't have the raw damage, but the range allows you to grind him into mincemeat from far away. Use high bloodtinge defense armor like maria's set, knight's set, or cainhurst set, as he will only be able to shoot you to hit you. The best attacks against him are (all of these are transformed moveset) backstep r2, dash r1, and regular r1. I usually keep my distance, use backstep r2s, when he gets close do 1 dash r1, and follow up with 1-2 r1s, back away, repeat. Hope this strat works for others too. Happy hunting.