Sebastian

Sebastian is a hermit crab with Jamaican accent, who is in service of King Triton in Atlantica, which is where Sora, Donald, and Goofy meet him for the first time. He is known as the one who tries to keep Ariel out of trouble, and keep her mind off the human world. He is also the Court Composer.

Kingdom Hearts
''Triton's concert master, a musical genius. The little crab is also responsible for keeping an eye on Ariel to ensure her safety. Whenever she leaves the palace, he's on pins and needles.''

He conducted himself in "The Little Mermaid" (1989).

Kingdom Hearts: Chain of Memories
Triton's music director and Ariel's guardian.

Sebastian is constantly scolding Ariel for her escapades, but only because he worries for her safety.

Kingdom Hearts II
''King Triton's Court Composer. You could almost say he's a musical genius. Sebastian's also in charge of keeping an eye on Ariel and make sure she stays safe. Right now, he's working on a very special musical.''

Kingdom Hearts
In Kingdom Hearts (game), he is shown with Ariel and Flounder running away from the Heartless. He helps Sora by getting acquainted to swimming in Atlantica by chasing Flounder. When they arrive at Triton's Palace, he remains with King Triton as Sora and the others leave. After Goofy talks about looking for the Keyhole, Sebastian, like Ariel, becomes interested in it as well. After Ursula attacks King Triton with the Trident, Sebastian wants to help Ariel and Sora take her down. He helps them get into Ursula's Lair by pressing a button in the wall no one else could reach.

Kingdom Hearts: Chain of Memories
In Kingdom Hearts: Chain of Memories, Sebastian has a smaller role. He is looking for Ariel and the Trident as well since they both go mysteriously go missing. He is then later shown looking for them around Ursula's Lair.

Kingdom Hearts II
In Kingdom Hearts II, Sebastian's musical abilities from the movie are finally shown. He is trying to use musical practice to get Ariel's mind off the surface world. When Sora and the others say that they will help her, Sebastian gets mad and doesn't want them to help her with finding Prince Eric. Sebastian in the game writes Under the Sea to help Ariel want to stay in the ocean where she belongs. Ariel is instead saddenned by the song and yearns for Sebastian to write a song about land and sea living in harmony, making Sebastian frantic over the fact that King Triton would find out about this. Sebastian goes a little bit too far when in his monologue, he spills the fact that Ariel is in love with a human. King Triton happens to be right behind him, and when he hears this, he is deeply angered.

After Ariel changes into a human, Sebastian tries to help her kiss Eric in time. After Ariel and Eric defeat Ursula, and King Triton gives the green light for Ariel to marry Eric, Sebastian complies with what Ariel once said earlier in the sea, and he writes A New Day is Dawning to show how the two worlds can join together in harmony. In the ending credits, he is attending Ariel and Eric's wedding.