My first instinct was Triton. Its a stretch bit if they go with the deleted concept of Ursula being his sister then his crown was hard won because he had to take it from her and banish her after she killed all their other siblings and his wife (the sister thing was deleted from the movie but added back on the Broadway shoe, and the fact that Ursula killed Triton’s wife and all their other sisters was added in the Broadway show later on apparently as I read recently :P) So that could be that. But King Stefan is an easier answer. The description sounds like him from the movie maleficent. So while I HOPE its triton (played by willaim Shatner:P) I think its Stefan.
"I could have the giant duck as my steed!" --Daniel Radcliffe
Keeper Of Tamara's Taser , Jafar's Staff, Kitsis’s Glasses , Ariel’s Tail, Dopey's Hat , Peter Pan’s Shadow, Outfit, & Pied Cloak,Red Queen's Castle, White Rabbit's Power To World Hop, Zelena's BroomStick, & ALL MAGIC