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In Greek mythology Abderus or Abderos was a divine hero, reputed by some to be one of Heracles' lovers (eromenoi), and reputedly a son of Hermes by some accounts, and eponym of Abdera, Thrace.
The paternity of Abderus differs according to the sources. Some say he was the son of the god Hermes. But according to other writers, he was the son of Thromius the Locrian. Still others claimed he was the son of Heracles's friend, Opian Menoetius, which would make Abderus a brother to Patroclus, the famous companion of Achilles who died at Troy. Pindar makes Abderus a son of Poseidon and Thronia.
He is mostly known for his tragic role in Heracles' Eighth Labor. Along with others, he helped Heracles capture the four savage mares of Diomedes the king of the Thracian Bistones. Heracles overpowered the grooms and drove the Mares of Diomedes into the sea and left them in the care of Abderus. However, while Heracles was away, the horses devoured Abderus. In revenge, Heracles fed Diomedes alive to his own mares. Heracles founded the city of Abdera near Abderus's tomb, where agones (Greek: ), athletic games consisting of boxing, pancratium and wrestling were held in his honor (but chariot races were banned in respect of how he died).
In some very different traditions, instead of helping Heracles with his Eighth Labor, Abderus (or Abdertis) was a servant of Diomedes, and was killed by Heracles together with his master and his four men-devouring horses.