What was the emperor's role at the colosseum festivities?

By the time of the emperors, the emperor was the only one who could afford to pay for a gladiatorial contest. So he had the role of paymaster. If he attended the bouts, he was usually awarded the position of editor, which was the top official of the games. The editor was the one who gave the "start" signal, determined a win, loss or pass, and warded the prizes.