Neptune

King Neptune is a triton and he is the King of the Seas of Andros.

Overview
He is the father of the twin brothers Nereus and Tritannus as well as the uncle of Aisha, and as such he could be the brother or brother-in-law of either King Teredor or Queen Niobe. Queen Ligea is his wife with whom he has three children,Nereus, Tritannus, and  Tressa.

Season 5
In Season 5, he decided to name Nereus as his heir but Tritannus, jealous, disrupted the ceremony and was sent to prison.

After Tritannus's escape, he disowned Tritannus and set out to hunt him down. He was later turned into a mutant along with Tressa when Tritannus invaded the palace. He made some minor appearances after the ceremony.

Trivia

 * According to Roman mythology, Neptune is the God of the Sea. The Greek equivalent of Neptune, Poseidon, is married to Amphitrite, a Nereid nymph, one of the fifty daughters of the God Nereus, and with her had a son: the marine God Triton, who is half-man half-fish.
 * Neptune is also the eighth planet of the Solar System.