Even more than the gratitude...being told that he's actually helping, and in particular that he's helping Cloud - someone he, or something wearing his face, has done so much harm to - means so much to Sephiroth that his breath actually catches when he hears the words. Guilt, regret, shame, helplessness...those feelings have been so much of his life. Long before Jenova.

He'd managed to help people, it's true, even in ShinRa. Other SOLDIERs. Civilians. Friends. This isn't the first time he's ever felt as though he's made a positive difference. But...it's certainly never been as much of his life as he would have liked. This feeling that maybe things are better because he exists.

He can never undo what's been done in his name, with his body, but...perhaps he can in fact make things better for the people he's harmed. And this is the first truly tangible proof of that. And, for the first time...his continued existence doesn't feel quite so selfish.

"I'm glad," he says, faintly. And even in those two words, his voice almost breaks.