Delphin

"I'm afraid you just missed my lieutenant Delphin, God of the Dolphins."

- Poseidon to Percy Jackson

Delphin (also known as Delphinus) is the god of Dolphins in the service of the sea god Poseidon. He is one of Poseidon's lieutenants.

History
When his master was wooing Amphitrite and she fled, Delphin went in search of her and persuaded her to agree to the marriage. For his service Poseidon placed him amongst the stars as the constellation Delphinus.

The Last Olympian
He is seen during Poseidon's battle with Oceanus, the Titan of the ocean; Poseidon tells him to give orders to Palaemon and his Shark Legions.

Appearance
"And there was a dolphin - just a regular dolphin, but it was staring at the map intently."

- Delphin's appearance

He looks like a regular dolphin, however, it is assumed that he can change into any appearance he likes.

Trivia

 * The Delphinidae family of Cetaceans is named after him.
 * The word Dolphin comes from his name.
 * Delphin is likely the constellation Delphinus.