Dos is the twin brother of Uno the Hedgehog. When his sister was adopted by Sonic, Dos was instead taken in by Shadow and taught to hate the world and everyone in it. Sometimes he is wary of his foster parent's teachings, but nevertheless seeks to carry on his legacy and show everyone he's not a hedgehog to ever be messed with. He has mastered 27 different languages but hates them all, and only speaks them when necessary. Otherwise he communicates with hand gestures and his trademark "Hmph!" One day his twin sister comes down with a terminal illness and he is forced to come to terms with his grudge against society and study to become a doctor to cure her. His favorite food are warheads.