Heracles brought Abderus and some other youths to help him capture the Mares of Diomedes. They took the mares and were chased by Diomedes and his men. Heracles left Abderus in charge of the horses and fought Diomedes. Abderus was eaten. In revenge, Heracles fed Diomedes to his own horses, then founded Abdera next to the boy's tomb.