In the message, a castle is left to Sonia, who revels in the idea of having a castle for the Underground headquarters. Sonic, Manic and Sonia arrive at the castle only to see an old, dark ...

Sonic Underground's story is like a fever dream. In this one, Sonic is a prince who comes from a royal bloodline. He also has a brother and a sister, named Manic and Sonia, respectively.