Regarding Shields (note)
The Shields are the most open faction of the FCC, since they even welcome teens and adults as applicants for their training, while all other factions normally start with training children.
Since the Shields act as sort of a private army, they tend to have a lot of variety between their respective groups. At all times, there are exactly 6 divisions of Shields. Their numbers are between 30 and 50 soldiers, but there are exceptions of course. The group of Shields, that is tasked with defending the FCC itself is the smallest with only 11 members total and don't count towards the divisions. They are the elite and the best fighters this faction has produced. Those 11 sometimes act as advisors or teachers on the training grounds, to make sure that the standard for the future generations stays at the top.
When one of the six division is deployed, or bought/rented by a respective client, the other divisions split and form another 6th. And every one of the division has a special leader, that is appointed through the supervisors, teachers and councilors, who is responsible for their soldiers and is in continuous contact with their faction leaders, deployed or not.