There seems to be no record of his killing his father. But the plot also has a certain basis. He is a problematic emperor. Before Commodus, the Roman emperor was always a good system for adopted sons to inherit. The emperor chose his successor and adopted him as his adopted son. However, Commodus was the biological son of the last emperor Horilo. In addition, Commodus's personality is far less than that of his father and other wise emperors before him, so he is suspected of usurping the throne. Therefore, the film weaves the plot into that Commodus killed his father in order to be emperor, and wanted to kill his successor.