Romulus is the true Prince of the rats. In the book he hides himself from the others and had dug out tunnels to get around. He had convinced all the other rats of the kingdom that he was completely insane, when in fact he was entirely sane. He has flaps of skin under his arms and between his legs, leading him to believe that rats and bats shared a common ancestor. Unfortunately, he was also shunned for this "aberration".
He helps Shade and Marina escape from his brother Remus. He later reappears in Sunwing offering his help to the bats in the war against the owls, but the war never happens. In the Silverwing (TV Series) he is seen as a submissive king who allows his brother to rule beside him. He seems to believe everything his brother says and follows him without much question. Shade and Marina finally convince him to stop his brother, and Romulus then takes over as King of the Rats.
Romulus and Remus are the names of the first Roman rulers that were raised by the wolf Lupa in Roman Mythology.