Poseidon

Poseidon is a deity in the lore of Dota 2. He belongs to the same pantheon consisting of the likes of Zeus and Mars. If the real life family tree of the Greek gods were to be used, then he should be the former's brother and latter's uncle. As the god of the waters, it's implied that he has authority over nautical matters.

Trivia

 * Poseidon is based on the god of the same name from Greek mythology.