User blog comment:BMHKain/SEASON VI Hints./@comment-25968390-20151006213015

UPDATE: Finally found info regarding Souya Tachibana.

He is a third year student at the age of 18, a Student Council Secretary, thus sees Kuon Sumeragi as his Angel X Angel rival and desires to join the Board of Executives, uses Ice Arrows, states that he believes he can do anything no problem if he can put some effort to it, he has an “unpleasant but unseverable” relationship with Asuma, who is a hot head, and (Secretly) opposes Kuon.

Raphael, Souya's Angel, is a highly intelligent Piglet on the Wing. She however, hides all this useful knowledge yet is sentimentally fond of Souya. She typically states quotes starting with something like "Pupupu-pu, then something understandably catchy enough to make sense, and not sound stupid. Primary example: "Pupupu, pu-let's go-"

That's all I can find out about for Souya Tachibana. If you do extended searching, you just might find this kind of info.

It's just a shame it didn't get a true sequel. This game needs more love.