Hearing Dwight say his true name, Silver finally understood who he was. At the time, she still wasn't a vampire knight, but she had heard of an upcoming vampire who was rising through the ranks at an incredible rate.
A great talent that everyone knew, and that said person, was Rowa in front of her.
Even when he became leader, he had relinquished that position fast moving on and deciding to become a Royal knight. The thing was about Royal knights, once someone accepted this position, they were expected to stay loyal to the current king and most of the time they would pass on with him.
Those that joined the Royal army would no longer have the opportunity to become king and they knew that. It was a way for them to prove their loyalty to that of the current king. But Rowa had changed all that.