User blog comment:MyoXotiS/The Alchemist Code Collab Dungeon: Love Never Fades (Last Stage)/@comment-33895395-20171207204714

I recently beat him by taking Sae as a helper unit.

After the rest of my squad had been killed, I activated her UBB (which took a while to fill up thanks to that annoying ability of his...) and he got cursed while my team got revived and clobbered him. So a unit that can revive your squad (Layla, Sae,Nimune, etc.) is also a good choice to take if you go up against him