Battle Chasers: Nightwar

Story related, can not be missed.

The Mana Rifts goes back to a pretty straightforward type stage with nothing to accomplish but to make it to the boss. The stage itself can be a little weird as there are lots of spots that look like you can't go that way only to have blocks appear from below to create a path. The bosses of the stage are shadow versions of whoever you have in your current party when you face them. They have some of your same attacks and bursts, but aren't massively powerful in comparison. Just focus on using your bursts and skills and try to take them down one by one. Once they have fallen, the dungeon will be completed and the trophy will pop.