The Shonen-gireina was a syndicate which in the 2050s was made up of newcomers to the UCAS. Most of them were young and had been kicked out of older, established gangs. Therefore they came to the UCAS in the hope of making it big in North America.
It focused on street crime and didn't care who got wasted as long as the Shonen got what it wanted. They were borderline psychotic and the other Yakuza kept them at arms length. As with many other Yakuza splinter groups they were supported by neo-fascist policlubs back in Japan.