It could be an original character created specifically for the fanfiction. Maybe a mysterious woman Jaune met during one of his adventures who he had a brief relationship with.
It's also possible that the mother could be a character that was only briefly mentioned in the RWBY series. For example, a fellow student from a different kingdom who Jaune had a fling with during a tournament or some other event. The fanfiction could then explore how this relationship was kept secret and how it led to the birth of his daughter.
Perhaps it could be Pyrrha. In some alternate universe or through some magical means, Pyrrha could have had a child with Jaune before her untimely death. This would add a layer of bittersweetness to the story as Jaune would be raising their daughter while also mourning Pyrrha.
One possible plot could be that Jaune discovers he has a daughter in a very unexpected way. Maybe she shows up at Beacon Academy one day, and he has to figure out how she came to be. He then has to balance his duties as a Huntsman with being a father, all while protecting her from the various threats in the RWBY world.
Well, Jaune in RWBY fanfiction can vary a lot. Sometimes he's the underdog who overcomes huge challenges, and other times he might have unique powers or a special backstory.
It could be because Jaune is a relatable character. He starts off as a bit of an underdog in RWBY. So, fans like to write stories where the other characters notice his potential and become obsessed with him as he grows.
You can find such fanfiction on popular fanfiction websites like Archive of Our Own. Just use the search function and enter the relevant keywords.
One idea could be that Ruby and Jaune are partnered for a special mission outside of Beacon. Ruby's speed and combat skills combined with Jaune's strategic thinking could make them a great team. For example, they might be sent to investigate a mysterious Grimm activity in a far - off village. Ruby can quickly scout the area with her speed, while Jaune plans their approach based on the information she gathers.
One possible secret could be about his family heritage. Maybe in the fanfiction, Jaune has a hidden connection to a powerful family in the RWBY universe that he's kept under wraps for some reason, like to avoid unwanted attention or because of some family feud.
His character could become more self - assured. Jedi are known for their confidence in their abilities, and Jaune might gain that as he masters Jedi - like powers.
Ruby would most likely be involved. She's the leader of Team RWBY and has a strong sense of justice. She would be determined to find Jaune no matter what. Weiss could also be involved as she has the resources and skills to help in the search. Her family's influence and her own combat abilities would be useful.
In some fanfictions where Jaune is cheated on, he often goes through a period of self - doubt. He might question his own worth and what he did wrong in the relationship. This can lead to him becoming more withdrawn or overly focused on self - improvement to prove himself.
One common plotline could be Jaune having unique training methods. For example, in some fanfictions, he might be trained by a hermit - like figure who imparts special combat skills. Another could be his relationships evolving differently. Maybe he forms closer bonds with certain characters earlier than in the original series due to the altered upbringing in the fan - made scenarios.