"Then take it back. Here I am." He sets down his pencil and spreads his hands wide, the faint tremor of exhaustion hidden as best he can.

By degrees, his tone darkens towards bitterness and dull anger. "You and yours, denouncing actions I have yet to take, certainly seem intent on causing the very future you complain about." He looks back up, a short, sharp jerk. "But I will not be bullied and badgered about things I haven't done. So as Braig says it, put up or shut up."

And the opportunity is there, even if Demyx is just a musician and performer. Xehanort is unarmed, and visibly too tired to resist even someone who's not a skilled combatant. If he wants vengeance, there's a perfect opportunity for retribution for years of trouble and unhappiness and worse.