Devouring Kris was shown in battle, I've seen it in this video surprisngly enough. From what I can tell, it robs a certain amount of SP from the target. There is another Overload he has called Mastema's Hatred, which I'm not sure what it does. This means so far Void Dark (For this boss fight only) has FOUR Overloads. Just want to leave this as a note as the page might need updating and he could possibly have more. I don't know the details as I think it only tells the details once he uses that Overload, and he seems to have free range to use whichever one he wants or all of them in a single turn.
- BleachBummer
I fought Void today, so I can say yes, he had used those ones you mentioned during battle. However I've seen no effect to the Hatred one
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Had to look up a walkthrough, but from what I can tell, Mastema's Hatred increases how much damages he deals I think. Someone please if they see him use that Overload, check to see what it does to confirm.
- BleachBummer