Boss: Oboro and Shadow Self
Attacks: Shadow Self, High Blade, Impulse, X Cutter, EX Pain & Suffering
Shadow Self's Info:
Attacks: High Blade, Impulse
For this one make sure your party is at least in the high 20's before fighting him and make sure you have a full EX gauge because they will help out a lot. When his clones appear, defeat them and on the next couple of rounds you should be able to beat him.