Well, one possible plot could be that the little brother has some unique magical abilities that are different from Elsa's ice powers. Maybe he can communicate with animals in the enchanted forest and has to use this power to save the kingdom from a new threat.
There could be a dark spirit that has been awakened by the little brother's emerging powers. This spirit is angry at being disturbed and decides to target the little brother. It causes chaos in Arendelle, blaming it all on the little brother. As the story progresses, the little brother has to find a way to either defeat or pacify this dark spirit to save his home and family.
Well, perhaps the fanfiction could be about how the baby brings Anna and Elsa even closer together. Since they already have a strong bond, the baby could be like a little miracle that makes their family complete. The story could show their daily life taking care of the baby, like singing lullabies and teaching the baby to walk, with a lot of cute and heart - warming moments.
He could go on ice - climbing adventures with Elsa. Since Tarzan is so good at climbing trees in the jungle, he might adapt well to climbing ice cliffs in Arendelle. And with Anna, he could explore the forests around Arendelle, sharing his knowledge of the wild.
Well, it could start with Elsa being conflicted about her feelings for Anna. She tries to hide it, but Anna senses something is different. As they work together to solve a new threat to Arendelle, like a new dark magic, their bond deepens. They finally confess their love for each other. They decide to get married in a ceremony that combines both Elsa's ice magic and Anna's warm spirit. The whole kingdom comes together to support them, and they use their combined leadership to make Arendelle a more inclusive and magical place.
One possible plot could be that the baby has special powers like Elsa. The kingdom is both excited and a bit worried. Elsa and Anna have to figure out how to raise the baby while also dealing with the reactions of the people. They might face some challenges when the baby's powers start to show early, like accidentally freezing things. But with love and support from each other and their friends, they manage to raise the baby in a happy and healthy environment.
One idea could be that Elsa and Anna discover a hidden magical realm within Arendelle. They meet new magical creatures there and have to work together to solve a problem that threatens both this new realm and Arendelle. For example, a dark magic is spreading and only Elsa's ice powers combined with Anna's courage can stop it.
Well, in fanfiction, anything can be possible. Maybe it could be due to some magical cross - over event. Perhaps a powerful magic combined the different worlds of Tarzan, Elsa, and Anna, and as a result, Tarzan became their brother in this fictional scenario.
Maybe the plot could be that in a small Arendelle village festival, they decide to have a square dance. Anna, being the more outgoing one, drags Elsa into it. At first Elsa is hesitant but then starts to enjoy the rhythm and the company. They meet new friends during the dance and it becomes a memorable event for both of them.
In this fanfic, it could be that Anna and Elsa lock arms as they embark on a journey outside of Arendelle for the first time together. Along the way, they encounter different cultures and challenges. Their locked arms represent their commitment to stay together through thick and thin. They learn more about each other's strengths and weaknesses and grow as individuals and as sisters.
The plot could involve the mother's spirit guiding Anna and Elsa on a journey to discover their true heritage. This might include visiting places that were important to their mother and uncovering long - forgotten family traditions.