Neleus

Neleus was the son of Poseidon and Tyro, brother of Pelias. Tyro was married to Cretheus (with whom she had one son, Aeson) but loved Enipeus, a river god. She pursued Enipeus, who refused her advances. One day, Poseidon, filled with lust for Tyro, disguised himself as Enipeus and from their union was born Pelias and Neleus, twin boys. Tyro exposed her sons on a mountain and they were raised by a maid. When they reached adulthood, Pelias and Neleus found Tyro and killed her stepmother, Sidero, for having mistreated her. Sidero hid in a temple to Hera but Pelias killed her anyway, causing Hera's undying hatred of Pelias.
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[Greek] The son of Poseidon and Tyro. He was the twin brother of Pelias and contested with him for the crown. Neleus moved to Messenia and became king of Pylos. When Heracles visited him with the request of cleansing him from a blood-debt, Neleus refused. Heracles destroyed Pylos, and killed Neleus with all his sons, except for Nestor.