Reapers, Aliens, and Mafia

Based on kakashiluckyblackcat's challenge. With a little extra.

Tsuna's life if far from normal, considering she's best friends forever with the Grim Reaper. At the age of seven, Tsuna met the Grim Reaper knew when she was helping an injured bird. And after Grimm lost a bet with her(they played a game of limbo and Nana surprised Grim, causing him to lose), he stays with Tsuna and her mom. In addition, they meet a whole bunch of interesting characters, including a alien from Irk which inspire Tsuna to write stories about the experience, and she's hailed as the next RL Stine.

When Reborn enters the scene, things really got crazy.

Grim Adventures of Billy and Mandy, Khr, and IZ crossover

Nergal jr. Is Tsunas first maternal cousin (Nana has a sister who marries Nergal) he's protective of Tsuna and loves his family.

Tsuna has two suitors; Jack O'Lantern, an immortal prankster, and Zim, an Invader from Irk.

Zim was an invader, until the Tallests tricked him into going to Earth and he stayed in Namimori as an outcast, but he has Junior, Grim, and Tsuna hang out with him.