ARC Recruit

Sometimes, Elite Clone Troopers and ARC-like Republic Commandos were chosen to be recruited as ARCs. They were put in a squad under the command of an ARC Captain.

The most notable of these were in Fordo's Squad, and were promoted.

Behind the Scenes
This is a fanon explaination for a canonical subject, which most Wookiepedians who debated on the subject greatly frowned upon.