Princess Bubblegum could be a part of the fanfiction. She might be interested in the unique flora and fauna of the Canyon and could send Finn on a mission there. Marceline the Vampire Queen could also be added. Maybe she has some history with the Canyon and her presence could add an element of mystery and danger.
Finn and Jake are often the main characters in Adventure Time Canyon fanfiction. They are the protagonists of the original show and their adventures are always exciting to write about in the context of the canyon.
Finn is the adventurous and somewhat naive human. His perspective is always interesting as he views the magical world of Ooo through the eyes of an outsider. The lady, whoever she is, usually has her own set of values and goals. If it's Flame Princess, for example, she has her power and her own kingdom to think about. Their conversations in the fanfiction are shaped by these aspects of their characters.
Obviously, Finn and the Jungle Princess are the main characters. Finn, a brave and adventurous boy, and the Jungle Princess, who has her own set of skills and knowledge about the jungle environment.
The main characters are Finn, a brave and adventurous human boy, and the Water Princess. Finn is known for his heroics and his sword - fighting skills. The Water Princess has control over water and is from the Water Kingdom.
A possible plot could be that there's a magical artifact deep in the Adventure Time Canyon that Finn is tasked with retrieving. However, the Canyon is guarded by a powerful being. Finn has to prove himself worthy to the being in order to gain access to the artifact. Along the way, he learns about the history of the Canyon and its significance in the Adventure Time world.
First, think about Finn's character traits. He's brave, curious, and has a good heart. Then, consider what the Canyon could represent in your story. It could be a place of mystery or a source of power. Start with an interesting situation like Finn getting lost in the Canyon or finding something unusual there.
The Lich could be a great antagonist. He might frame Finn as part of his plan to spread chaos and death in Ooo. Since the Lich is always looking for ways to disrupt the peace, using Finn as a scapegoat would be a clever move for him.
It could also be a corrupted version of one of Fionna's friends. For example, if Cake were to be turned evil by some dark magic. Cake would know all of Fionna's weaknesses and could use that knowledge against Finn in his Fionna form, making her a formidable and tragic antagonist.
There's a fanfiction where Finn discovers a hidden part of the Canyon. This fanfic delves into Finn's sense of wonder and his relationship with the Canyon. It might include elements of mystery as he tries to figure out the secrets the Canyon holds. Maybe he meets some new creatures there that change his perspective on the Canyon and his adventures in general.
The main characters are obviously Finn and Huntress Wizard. Finn, a brave and adventurous human boy, is known for his heroics in the Land of Ooo. Huntress Wizard, on the other hand, is a mysterious and powerful magic - user.