Some scholars have speculated that Mark Antony may have been bipolar, and cite his extremes of temper and habit of changing sides as proof of his instability.
Vorenus rejoins the legions as an "evocatus". This was the Latin term for a soldier in the Roman army who had served out his time and obtained a discharge (Latin, "missio") but had voluntarily enlisted again at the invitation of the consul or other commander. The position was a plum one, as they were essentially high-ranking officers, and did not have to take part in manual labor duties.
As a prefect (Latin, Praefectus) Vorenus has the position of civil administration, as well as that of captain of Antony's guards.