Ariel

Ariel is the seventh-born daughter of King Triton and Queen Athena of an underwater kingdom of Atlantica. She longs to be a part of the human world. She marries Prince Eric, whom she rescued from a shipwreck

The Little Mermaid
Ariel is shown as being adventurous and curious about the world of humans, a fascination which angers both her father King Triton and his court composer Sebastian, as merfolk are not allowed to make contact with the human world. She and Flounder go in search of human objects, which they take to a seagull named Scuttle for appraisal. Ariel falls in love with a human prince named Prince Eric after saving him from drowning, and visits the sea witch, Ursula, who agrees to turn her into a human in exchange for her voice. Ariel must make Prince Eric fall in love with her and romantically kiss her within three days, lest she belong to Ursula forever.

Unknown to Ariel, this agreement is part of Ursula's bigger plan to trap Ariel's father, King Triton and steal his magical trident. After being transformed, Ariel found that she can no longer breathe, nor swim. Sebastian and Flounder take her to the surface. She is soon found by Eric and is taken back to his castle. Ariel almost manages to obtain the "kiss of true love", but is stopped by Ursula's underhanded tactics. On the third day, Ursula transforms herself into a human, calling herself "Vanessa" and using Ariel's voice, and bewitches Eric to make him marry her. After learning from Scuttle that the woman is Ursula in disguise, Ariel disrupts the wedding and regains her voice but the sun sets as Ariel and Prince Eric are about to kiss, transforming Ariel back into a mermaid. After transforming herself back into her true witch form, Ursula takes Ariel back into the ocean, where she is met by King Triton and Sebastian.

Triton trades himself for Ariel, enabling Ursula to steal his crown and enabling her to claim his trident, a fascination which angers Ariel, who will not allow Ursula to destroy merfolk and humans. In the battle that follows, Ariel is trapped at the bottom of a whirlpool. Before Ursula can destroy her, Eric kills Ursula by ramming a derelict ship's splintered prow through her. After Ursula dies, her spell is broken, and King Triton and the merfolk are transformed back to normal merpeople. At the end of the film, after King Triton uses his magical trident to transform her into a human, Ariel leaves the sea to live in the human world, and she and Eric marry and live happily ever after.