I haven't actually read this specific fanfic, but generally in a 'Ben x Esther' fanfic in the Ben 10 Omniverse setting, it might explore their relationship in different ways. It could involve adventures where they team up, and their characters' growth while dealing with various threats in the Omniverse. Maybe it also delves into how their different personalities interact and complement each other.
The theme of redemption can also be present. If Accelerator has some dark past or actions, Esther could be the catalyst for his redemption. Fanfictions might show how Esther's presence and influence gradually change Accelerator for the better, and how he starts to view the world and his own actions in a new light.
Another place to check could be some dedicated anime or manga fan communities. For example, Reddit has various sub -reddits focused on different anime series. There might be threads where fans share or discuss Accelerator x Esther fanfiction. You can also ask in those communities if anyone knows where to find such fanfictions.
One common theme is friendship. Most fanfictions explore how Nigel and Isaac become friends, support each other, and have a great time together. Another theme could be self - discovery. They might learn new things about themselves through their interactions.
One great Isaac Lahey x Reader fanfiction is 'Moonlit Encounters'. It beautifully captures Isaac's complex personality and the relationship with the reader. The author does an amazing job of building the tension and chemistry between the two characters.
In 'scott x isaac fanfic', the theme of growth is quite prevalent. Both Scott and Isaac can grow as individuals within the relationship. This could be in terms of their powers (if they are from a universe where they have powers), or in terms of their emotional maturity. Another theme is the idea of acceptance, accepting each other's flaws and differences, which is often a central part of their relationship in these fanfics.
Since I don't know the exact story, Esther Jane could be the main character. She might be a girl or a woman who has a special connection to Christmas in the story.
One possible plot could be that Esther gets caught up in an alien conspiracy in the Omniverse. Ben, being the hero, steps in to save her. As they work together to uncover the truth behind the conspiracy, they start to fall for each other.