Antonius Proximo was a wealthy slave owner who owned Ex-Roman General Maximus Decimus Meridius, Numidian tribesman Juba, the Barbarian from Germania, Hagen, and a lot of other Gladiators from across the world. He himself was a Gladiator who was freed by the Roman Emperor Marcus Aurelius. He oversaw many Gladitorial Games where his slaves participated in, and he later befriended Maximus.
He advised Maximus that he would not make it very far as a Gladiator if he continued killing his opponents with such obvious ease and speed. He constantly reminded him that in order to be the best, he needed to "win the crowd".
He was later trusted enough by Lucilla, to be privy to her visits to Maximus, where they planned their coup against the Emperor. Initially Proximo was unwilling to help, acknowledging that whilst Maximus was a good man, he was simply "an entertainer". However, he quickly decided to help Maximus after he was informed that "He killed the man who set you free." (referring to the fact Commodus killed Marcus Aurelius).
Gladiator once Again
When Roman Emperor Commodus sent a regiment of men to raid the school, Proximo defiantly refused to open the gate for them. Instead, he walked across the courtyard in full view of the soldiers, and set the gladiators free. Maximus remarked that he was "in danger of becoming a good man".
He then returned to his tower, holding the wooden sword that the previous emperor, Marcus Aurelius had given him, presumably reminiscing about his life, in the knowledge he was about to die (for disobeying the troops). As the troops burst in, he stood straight, repeated his motto "[Us mortals are but] Shadows and Dust.", and was butchered.