lol. next girl would probably be a lesbo or something. I'm starting to think that MC should just resign himself to being a magnet for girls with fetishes
Man, this made me laugh real hard!
Also with how this is going I can totally see that thr best friend is indeed the cinderellla be it a reverse trap or just a pervy dude in love.
If the sister is yandere, then also nope, nope, nope... but if she's a brocon then ok. Other than that the masochist would be the best choice out of the crazy ones.
Why are people even speculating at this point?Sister is 100% brocon and perhaps the source of the letter,no doubt a wicked fetish is also within her psyche(incest maybe?).
I got an idea for the final plot twist:
The one who placed that letter should be Shouma who actually is into the MC!
Either that or Shouma placed that love letter to stir things up seeing how is friend is seemingly surrounded by lots of girls who got a thing for him but the MC does not notice it.
So then Shouma, to "help" his friend and advance his friend's private life to finally hook up with one of the girls, wrote that letter and put it into the MC's shoe locker.