The Legions are called the Alscoria (approx 2,300 men divided into two Seneva of 1,000 men, subdivided into Mellin of 80-100 and an Almae of 300 cavalry.) Clearly there will be no major battles as Oblivion cant handle it but there will be plenty of military action and you can either be one of the barbarian peoples or a Holorian citizen.
Specific arena armour and weapons would be very good. You could have a field day on that alone, the outlandish for spectacle and the downright evil!!