She could have an adventure where she helps Ariel understand the surface world better before Ariel makes her deal with Ursula. Maybe she uses her knowledge of the sea and its rules to guide Ariel safely.
In some fanfiction ideas, Attina could be the one who discovers Ursula's true evil intentions long before anyone else. She could then try to stop Ursula's plan from the shadows. For example, she might try to find evidence of Ursula's wrongdoings to convince King Triton. This would be a really interesting story arc as it would show Attina as a more proactive and intelligent character.
A sea witch could be a great antagonist. She might be jealous of Attina's beauty and grace, and try to use her magic to turn Attina into an ordinary fish. The sea witch could also create all sorts of obstacles for Attina and her friends, like summoning sea monsters or causing storms.
She could be portrayed as a rebel. Instead of always following the rules of the mermaid kingdom, she might start to question them and lead a movement for change among the mermaids.
One idea could be that Attina discovers a hidden underwater cave filled with ancient mermaid magic. This magic could give her the ability to communicate with sea creatures in a more profound way. For example, she could understand the thoughts of whales and dolphins and use this knowledge to protect the ocean from human pollution.
She could have adventures like trying to find Jack's hidden artworks. Maybe she discovers a secret about the Titanic's construction that Jack was also starting to figure out.
Well, perhaps Mermaid Man and Barnacle Boy could face a new super - villain. Maybe a villain with the power to control the tides in a very dangerous way. They would have to use their old - fashioned yet effective gadgets to stop this new threat.
Maybe it could be about the little mermaid's new adventure in an undiscovered underwater kingdom. She might meet new friends or face new enemies there.
Triton could embark on an adventure to find a lost magical artifact. This artifact is said to have the power to protect the entire ocean from any harm. He sets off with a small group of his most trusted mermen. Along the way, they face dangerous sea monsters and tricky underwater mazes. Triton uses his trident to fight off the monsters and his wisdom to navigate the mazes. Eventually, they find the artifact in a hidden underwater cave guarded by an ancient sea spirit. Triton has to prove his worthiness to the spirit to obtain the artifact.
She could have adventures exploring the unique Kalosian landscapes. Maybe she discovers new Pokemon species that are native to Kalos. For example, she might come across a Fletchling in one of the beautiful forests of Kalos and try to befriend it. This could lead to a whole new journey as she learns about the behavior and characteristics of Kalos Pokemon.
She could have adventures with magical farm animals. Maybe there are unicorns in the fields that she befriends and they help her protect the farm from dark magic threats.
She could have encounters with magical creatures that are rarely seen outside the forest. For example, she might come across a group of centaurs and have to earn their trust through her intelligence and respect for their ways.