It could be an original character. For example, a young girl who discovers she is half - Grimm after an accident. She has to hide her true nature from others while trying to understand her powers.
Maybe a side character from the RWBY series who is secretly half - Grimm. This could be someone who has always seemed a bit off or had unexplained abilities. Their journey of self - discovery and acceptance would make for an interesting story. They might have to face their friends and reveal their true identity, which could lead to various reactions.
It could also be a new type of Grimm hybrid created by some sort of scientific experiment gone wrong. This character would be confused about their existence, having the instincts of a Grimm but also a sense of self - awareness like a human. Their struggle to define themselves in the RWBY universe would be the central focus of the fanfiction.
One concept could be that the OC is a half - Grimm who struggles with their identity. They might be shunned by both humans and Grimm at first. But as the story progresses, they use their unique abilities, like being able to sense Grimm better than humans and having some Grimm - like strength, to help the RWBY team in their battles. For example, they could be able to sneak into Grimm nests without being detected as easily as a normal human.
I think Jaune could be a likely candidate. He's a main character with a lot of development potential. His insecurities and his strong will to become a better Huntsman could be twisted if he were turned into a Grimm. It would create a great internal conflict as he battles his new nature.
It could be a rogue Huntsman who wants to use Ruby's power to control Grimm for his own evil purposes. He might believe that with the Grimm under his control, he can rule over Remnant. He would then be constantly trying to kidnap Ruby or figure out the secret behind her power, and would oppose team RWBY at every turn.
In some RWBY fanfictions, the idea of Ruby being half Beowulf Grimm can be a creative and out - of - the - box concept. However, in the official RWBY canon, there is no such indication. Fanfiction writers often like to explore unique and alternative storylines that deviate from the original lore, and this is one such example.
I'm not entirely sure as it's a fanfiction, but it might feature the main RWBY characters like Ruby, Weiss, Blake, and Yang. Since it's about the Grimm beginning, they could be portrayed in their early days, perhaps just starting to learn about the Grimm and their own powers.
The main character, the child of Grimm, would be at the center. They may have a mentor figure, perhaps an older Huntsman or Huntress who sees potential in them despite their Grimm origin. Then there could be antagonists specific to the fanfiction. Maybe there are those who want to use the child of Grimm for their own evil purposes, like some power - hungry villain in the RWBY world.
Since it's a fanfiction, it could vary a great deal. But likely, it would include some of the main RWBY characters like Ruby, Weiss, Blake, and Yang. Maybe there's a new character who is the so - called 'King of Grimm' that they have to face or interact with.
It could be a powerful Grimm - like being that has evolved beyond the normal Grimm. This antagonist might have the ability to think and strategize like a human, making it a much more dangerous foe for Ruby and her team. It could be leading the Grimm attacks in a more organized way, targeting specific areas to cause maximum chaos.
There could be an ancient Grimm entity that has been dormant in the Pacific for ages. Due to some recent events, it wakes up and starts wreaking havoc. It has the ability to corrupt other Grimm and make them more powerful and intelligent. This entity would be a formidable antagonist for the RWBY team as they try to stop its reign of terror in the Pacific region.
In RWBY fanfiction, if Ruby is half Beowulf Grimm, it could mean a significant change in her abilities. She might have some Grimm - like powers, such as enhanced strength or a different form of combat. For example, she could have the ability to sense other Grimm in a more instinctive way.