One common theme is the exploration of power. Both Eclipsa and Star have significant magical powers, and fanfictions often focus on how they control, develop, or struggle with their powers. For example, some stories might show Star learning from Eclipsa's more ancient and perhaps darker forms of magic.
One great piece of fanfiction might be 'The Adventures of Eclipsa and Star'. It has an interesting plot where they team up to solve a mystery in the Magic Dimension. The author does a wonderful job of capturing their personalities.
A common plot element is their interaction regarding magic. Since both are related to magic in the show, fanfictions often explore how they exchange magic knowledge or work together to solve magic - related problems.
Star would be an obvious choice. Their different approaches to magic and their positions in Mewni society could create a lot of interesting interactions. Marco could also be a good character to pair with Eclipsa. His down - to - earth nature could contrast with her more otherworldly and mysterious self. And Moon could be another. There's a lot of history between them, and exploring their relationship further, whether it's a begrudging alliance or a slow - burning friendship, would be great.
There are various themes in eclipsa and star fanfiction. For example, some fanfics might be about how eclipsa, with her unique powers and past, influences star's growth as a princess. Others could be set in alternate universes where their roles are slightly different, creating new and interesting storylines that deviate from the original plot but still keep the essence of their characters.
It could be an ancient, powerful demon that has been awakened by the chaos in the magical realms. This demon might have a vendetta against Eclipsa's family specifically and wants to destroy her line.
One idea could be that Eclipsa discovers a new, hidden power within herself that gives her an edge against the forces of evil. Maybe it's a long - lost spell from her ancient lineage. Another could be a team - up between Eclipsa and some unexpected allies from different realms to fight the forces of evil.
A great plot idea could be that Eclipsa discovers a hidden power within herself that is both a blessing and a curse. She has to figure out how to control it while also dealing with the politics of Mewni. Another could be a time - travel fanfiction where Eclipsa goes back to key moments in Mewni's history to change things for the better. And one more idea is that Eclipsa starts a school for different kinds of magic, which causes a stir among the traditional magic users in Mewni.
I recall a fanfic called 'Jealousy's Grip'. In this story, Star's jealousy is triggered by a misunderstanding. The story takes an exciting turn as Star tries to figure out the truth while dealing with her emotions. It's a short but intense read that captures the essence of the 'jealous' theme really well.
I'm not sure specifically as I haven't read that particular fanfic. But generally, in 'Star vs the Forces of Evil' fanfics about Eclipsa, they might explore her backstory, her relationships within the show's universe in new ways, or create new adventures for her character.