Nero did not leave the arena. Instead, he walked up to Silas who looked both queasy, and determined. After a week's worth of training, it was time for him to fight Andrew again. For one week, Nero had regularly taken out time to slowly teach Silas, giving him pointers and training, as well as sparring with him as well.
When Nero was not available, Silas would spar with others in his own battalion. He had a decent standing in Demeter, and the battalion was doing especially well with its new batch, so he had more than enough people to train with.
Yet Andrew was not idle either. He had been full of resentment, not just from getting beaten up by Nero, but facing a tough battle at Silas' hands. Thus, he had also trained furiously, aiming to get his revenge on Silas. Secretly, he was even aiming to get his revenge on Nero… until he saw the fights against Vilhelm, that is. That's when he realised just how easy Nero had gone on him.
