I might have to change a few things about Kasugo's looks (present Kasugo) because his hair and eye color (plus the whole scar thing and a little of the backstory) are similar to a character named Alexander-Her (Sasha) from the manga called Seikon no Qwaser. Though It's a really good manga so far. It has a lot of nipples and nipple sucking.haha I might use pink-haired Kasugo as the default appearance.
I actually pictured something like this with Kasugo when he would encounter Twin again after receiving his scar:

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