Milo's family have been heavily involved in the gang called Cosa Nostra since it was founded, not long after the founding of Shipsister itself, in 370. In the centuries since then, the Cosa Nostra (a term derived from an Earth term for organized crime) has controlled virtually all crime in Shipsister. Unlike the gangs of other villages, the Cosa Nostra has always taken its work seriously, and employed relatively few teenagers. In fact, it is often considered a model for what gangs would become in 899. Because of that, most modern gangsters hold a great respect for them. Both LandOrder and InterGang were reportedly eager to convince the Cosa Nostra to join them, as were several other inter-village gangs (which didn't last beyond the Coming of the Order). But the leader of the gang at the time, a man named Henrik, had no interest in joining any upstart inter-village gang.
Leadership (or membership of any level) in the Cosa Nostra has never been a strictly familial thing, despite what many outsiders believe. Anyone can join, and anyone can rise to the upper ranks. It is true, however, that there are a few families in Shipsister that have contributed more members, through the generations, than have any others. And Milo happened to come from one of those families. Of course, his relatives all had other jobs, to keep them connected to the "common man," to maintain contacts that might be useful to the gang, and just to have skills to fall back on. Many members of his family never even worked for the gang at all. Milo himself worked as a Longshoreman for many years, which was a common occupation in his family. (It also often came in useful in the gang, which did a great deal of "business" with various shipping companies.) The work he did for the gang both in his capacity as a longshoreman and as a gangster was well-regarded by his superiors, and he steadily rose through the ranks. When Henrik retired in 903, Milo was voted the new leader of the Cosa Nostra.
In spite of Milo's respect for Henrik, he believed it would be in the best interest of the gang to join one of the inter-village gangs (particularly now that it was clear two of them were going to last). So he began talks with both LandOrder and InterGang. It was about this time that Jack, the head of the BiShip Brigands in Ship, was doing likewise. But in early 904, before either Milo or Jack had come to any agreements with either inter-village gang, the Laser Plot took place in Ship, which led to the police working harder to crack down on crime in all port villages. The larger gangs therefore decided having branches in Ship or Shipsister would be more trouble than it was worth. This led Milo and Jack to unite their two gangs as BiShip. It was then that Milo became the first leader of the Cosa Nostra to use the term 'don.'
Later in 904, when the surname law was passed, Milo chose the name 'Longshore,' for obvious reasons. Jack, meanwhile, took the name 'Dockrat.'
In 912, Tiejo Streetrat joined a group of rebels called The Chaos. He began asking his 'rat friends in various villages if they could organize a secret army to aid the Chaos. When it came to Milo's attention that one of Tiejo's friends, George Dockrat, was organizing 'rats for this purpose in Shipsister, he offered his assistance, as well as putting George in touch with Jack Dockrat (no relation). This led to the 'rats of Ship helping sabotage the naval base in that village, during the Battles of East Ports.