The Estraneo Famiglia is a Mafia family in the Katekyo Hitman Reborn! series. Infamous for its questionable experiments, it is the organization that Mukuro Rokudo, Ken Joshima, and Chikusa Kakimoto were born from.
Due to the invention of the Possession Bullet and the experiments conducted by the Famiglia, the Estraneo were labelled as brutals, leading other Mafia families persecuting them. According to Ken, as soon as members of the Famiglia stepped outside, guns were pointed at them, and they were killed like bugs. The killings only motivated the adults of the Famiglia in continuing the experiments to invent special weapons, using children of the family as "guinea pigs". One of the researchers of the Estraneo Famiglia stated that the invention of the special weapon was a stepping stone for the Famiglia to restore their fallen glory. He also said that the children who were experimented on, should "Think of it as an honor to die by being a part of the development". The children of the Famiglia were dying one by one as a result of the experiments.
Later, when Ken and Chikusa seemed to be the only surviving children left, in the middle of an experiment, Mukuro killed all of his captors with his Six Paths of Reincarnation. With Mukuro's rebellion, all the members of the Famiglia were killed, ending the Famiglia's existence.
- Estraneo means "stranger" or "outsider" in Italian.