Cosa Nostra

The Mafia (also known as Cosa Nostra) is a criminal syndicate that emerged in the mid 19th century Sicily. It is a loose association of criminal groups that share a common organizational structure and code of conduct. Each group, known as a "family", "clan", or "cosca", claims sovereignty over a territory in which it operates its rackets – usually a town or village or a neighborhood (borgata) of a larger city.

Anime
In the anime, the Cosa Nostra is run by the Greone family and is featured in the Intoccabile Acte I and II.

Les Soldats and the Cosa Nostra have a common past. Les Soldats were there to witness the Cosa Nostra when they were first formed, which makes Les Soldats a much older group.

Don Salvatore was once the head of the Cosa Nostra before he was killed by his granddaughter, Silvana. Once she killed him with her family's dagger, she took control of the group as the Intoccabile one.

There are a group of three men that work for the Cosa Nostra called the Mafia Saints. The three work for the Cosa Nostra without a second thought.