User blog comment:MyoXotiS/The Alchemist Code Collab Dungeon: Love Never Fades (Last Stage)/@comment-26947994-20171209202309

Thank you for this info! I got wrecked by Logi and I decided to wait for some way to defeat him.

But how are we supposed to figure this out by ourselves? There is no indication that we're not supposed to use Light/Dark units, so it's pretty much impossible to complete the quest unless one gets really lucky...