The Twin's Curse 『Katekyo Hitman Reborn Fanfic』

『Curse- A solemn utterance intended to invoke a supernatural power to inflict harm or punishment on someone or something.』 Tsuna's twin sister, [Name], is cursed and he can't do anything about it but to watch how his sweet sister changed into a cold person. And now he has more problems to deal with which is the Mafia...