Um, so I've trying to find a manga where the MC has a twin, both of them were known as being seriously ruthless killers, who disappeared from an academy so he goes on an undercover mission to find out who killed his twin. At the academy he befriends a 'timid' boy, the crown prince is apparently behind the murder and can do some mind-controlling thingy(?).
That's the gist, I can't remember most but I hope someone can can help me; I've been searching for a month ;-;
http://www.mangago.zone/read-manga/chi_to_chocolate/ I hope this is the one you're looking for.
Been a long time since I've wanted to slap every lead in a story.
ML - irredeemable piece of trash. If that estate burnt down with him alone in it, I would only save him once his face and body suffers third degree burns so he has to live out a miserable existence.
MC - she should have tried to leave the estate as soon as possible. She's not dumb or naive, she clearly knows abt her situation even super early on, so why why why not formulate a plan to escape as fast as possible DDDDDX
ML's fiancee - C'MON at least cook up a plot to marry the MC off, where's the villainess and their petty ego at when it actually matters AND WOULD BE IN GOOD SERVICE
Kyle - a humongous green flag, only flaw is being a coward so he's not well-suited for the MC. hard to blame him when most ppl are susceptible to societal pressure and familial expectations.