In some fanfictions, Ariel's death might be a tragic result of a broken heart. Maybe after Eric chose another, Ariel, in her deep despair, could take her last breath while looking at the sea that she once left for love. It's a really sad concept as she sacrificed so much for a love that didn't end well.
It could be that Ariel has been poisoned by some dark magic from an enemy of the sea. As her strength fades and she takes her last breath, she looks towards the surface of the ocean where she first saw Eric. In her last moment, she remembers all the adventures she had on land and underwater. Her last breath is a testament to her courage to explore and love beyond the boundaries of her own world.
Ariel's last breath could be a turning point if it leads to a magical resurrection. For example, her love for Eric and the sea could be so strong that it triggers some ancient magic. Her last breath releases a powerful energy that not only brings her back to life but also changes the relationship between the humans and the mer - people. It could be the start of a new era of understanding and peace.
Another reason might be environmental disaster in a fanfiction. If the ocean was being polluted at an alarming rate and Ariel tried to fix it but was exposed to too many toxins. As she took her last breath, she would be sad about the future of her ocean home and the creatures she loved.
Perhaps in the fanfiction, Ariel and Eric get married and have to deal with the cultural differences between the underwater world and the human world. For example, Ariel has to learn the proper etiquette in Eric's kingdom while Eric tries to understand the unique traditions of Ariel's mermaid family.
There are several possible reasons. Maybe she has lost something precious in the fanfiction. It could be a magical item that was important for her connection to the sea. Or perhaps she has had a fight with a friend or someone she loves. This emotional distress makes her break down in tears as she tries to deal with the situation.
In a fanfiction scenario, Ariel takes her shoes off when she reaches the shore. As she does so, she feels a strange connection to the land. It's as if the act of removing her shoes makes her more attuned to the human world. She starts to learn about different types of shoes that humans wear and even tries to make her own, using materials from the ocean. This leads to some humorous and heartwarming interactions with local villagers.
Perhaps in a fanfiction, Ariel and Eric will have a family of their own. They will raise their children to understand both the land and the sea, creating a unique bond between the two worlds.
One possible fanfiction could be that Ariel and Eric discover a hidden underwater kingdom that was lost long ago. They embark on a journey to learn about its history and find that it holds the key to a magical power that can save both the underwater and land worlds from a new threat.
Often, in fanfiction, Ursula can still be a main antagonist. She might come back with a new plan to break up Ariel and Eric, maybe using a different form of magic or disguise this time.