Nana heralds from a family of serial killers. She neglects to mention this to her husband, but when Iemitsu makes it clear he doesn’t expect Tsuna to join his family, Nana brings him into hers. This becomes a problem when Iemitsu changes his mind...

Tsuna is not quite human, neither are his guardians. Magic and flames can have some odd interactions.

In which Tsuna isn't Tsuna but Tsunako, and lived with her parents in Italy for a few years before circumstances made moving to Namimori seem advisable. And changes spiral out from there. For the prompt Xanxus/Tsuna - genderswap; "don't look down on me because I'm a woman."

Tsuna and his guardians died in a blaze of glory. Then they woke up, slowly, one at a time, in a different world that was the same in all the ways that really mattered. Or the one where Tsuna and his guardians are reincarnated into the class below the Konoha rookie nine.

Hibari Kyouya travels in time and takes over the world.