The Main Crew is a nickname for the group of main protagonists of the Roman Franchise, a changeable team of heroes commonly seen fighting Magnus Maximus's plans.
In the second Roman Film, Morien chooses to leave and Rhiannon joins the crew.
Before the destruction of the Wendaron Village by the Romans, Morien, Gaius and Iolo were already friends. Morien, as the heir to be laeder of the tribe, would meet up with the other two between Gaius's training, Iolo's shepherding and his own duties. Arminius tried to gain the Celts' trust before the attack, but was driven away by Morien's mother and father, and Gwydion. Arminius only became a member of the Crew when he met with Morien and Gaius at Coed Cai and they agreed to work together to prevent Magnus Maximus's plan to release the dragon. When they reunited with Iolo he also agreed to let Arminius help.