Actually, got the full version already. But then again, kudos to this vid for letting me notice the song. I think the singer was the one who VAed Shiina aka Kiriya's default sidekick. Yeah I know she's the default leader of the Luminous Knights, but still if I'm not wrong, this game is all abt Kiriya and Xecty to a certain extent. Interesting to know that Shining Tears x Wind was actually Souma's side of the story.
And lastly, I'm an official shipper for Kiriya x Xecty. Both Shiina and Kureha just don't fit in that well compared to that hot Celestia clone. In fact, Xecty will be the perfect girl to bear Kiriya's kids. Simply put, Kiriya x Xecty ftmfw.