Welp. Looks like the cat's out of the bag.... or not!
Until a dialog explicitly confirms it, it still leaves open the possibility that this character in question is a tomboy or a reverse-trap.
I'm pretty sure and interpreted it as if it were the character from this character.
The one who's in love with Kaoru's classmate who's in love with Kaori; the frame here does not show it, but in the other story the character clearly has mammary development.
Indeed, both are stated to have the given name — Miruku, so this is hard to deny.
@trapsarebetter
Oh i think i missed this chapter. Thanks btw.
I guess it was their PE shirt's color scheme that gave it away for me. (blue for boys, red for girls)