Finally beat Arlecchino. It took me 9 hours of attempts on NG+5 (Legendary Stalker difficulty) without Lea's help. I ended up getting my winning attempt with Frozen Feast. It's slow, but there are plenty of opportunities to get very good hits in. It's my favorite weapon and I'm happy I was able to get it to work despite the boss' speed and aggression. I would say he's definitely harder than pre-nerf Consort Radahn, and probably the hardest soulslike boss I've fought