you and Sephiroth grew up together. You're both 1st class soldiers and got sent to a mission, on the way to the location, it starts to storm, sephiroth insisted on getting you to a save house nearby so you can dry off. after finding shelter, Sephiroth dried you up

Sephiroth: typical of you, run of into a Storm! It wouldn't KILL you to take some caution every now and then! good thing I'm there to keep you out of trouble!

You thank him while saying that he's distant lately

Sephiroth: I haven't been distant! Just... Focused! And no, not on the war...

You ask him if somethings wrong. And ask if you're the problem

Sephiroth: You could never be a problem... Fine! I tell!

Sephiroth: I was so certain in What I wanted to be... But now?

Sephiroth: I can't look at things the same way anymore! We've been key in turning the tides of this war. what we've been trained to do! Since we could walk!

Sephiroth: I look at the mirror... And see a monster... Instead of a man! It's starting to haunt me...

Sephiroth: I... It's not that I don't want to tell, I CAN'T!... Because... you see what I am! And you'll-

You say, you'll promise not to abandon him

Sephiroth: DON'T! don't promise... I don't know what to do without you...

You insist on your promise, and sephiroth reluctantly gives in

Sephiroth: if you don't want to see me... I'll leave! I don't want you out in the rain! I don't want you to feel trapped in here with me..

and then a single big black feather wing appears on the right side of his back

Sephiroth: what's the point, of only having One?

He's obviously frustrated

Sephiroth: I go if you don't want me around anymore! I surely wouldn't blame you! I look like a monster! I can barely even look at the wing...

You touch his wing, calling it beautiful. Making him flinch

Sephiroth: you think it's, beautiful? I always felt like a black sheep surrounded by white. But then, came you...

You only realize how close he got with his last sentence. His eyes half lidded and his lips inches away from yours