This rabbit demon is from an upcoming WIP game called, "Street Devil" made by Jumpbreak96, and she will be the perfect choice for Y/n's rival. And to be completely honest, she looks like if Hank J. Wimbleton and Bloody Bunny had a baby. The game is still under development and there's not much information about this character. So, I'll do my best to explain about her with the info I can find about this interesting character.

How would they meet: How Y/n and Beltz would meet face-to-face will be in a similar scenario from One Punch Man when Saitama encountered Speed o' Sonic after the caped baldy managed to defeat the leader of the Paradisers named Hammerhead and Y/n will do the same exact thing only with a few extra scenes like being chased down by Beltz and fight against her for a little while until Y/n takes her out. This will result in Beltz finding herself a worthy opponent and will get her revenge on Y/n no matter what and will not rest until she will defeat her rival.

This video would be the perfect example of how they meet but in a different path: 

https://youtu.be/lE8JpP9VZw4

Her Likes: Listening to music that will put her to sleep, eating ice cream, intimidating, taunting and fighting against Y/n as her rival.

Dislikes: Being teased around by Y/n and other characters, someone changing her music playlist, someone eating her ice cream before she could, being bested by Y/n multiple times during their encounters.

Weapons - Her Hoverblade: 

https://youtu.be/5glpJIdpbzM

https://youtu.be/FTtwd69QBPI

Note: Her Hoverblade is her weapon of choice, that not only uses as a weapon as a battle axe or a sword or any type of weapon, but as a mode for transportation as a hoverboard that she can use to hover around places.

How she will react when she learns about Y/n's identity: She would be shocked to be fighting against a human being like Y/n and she will soon slowly develop some feelings towards Y/n and will try to hide her romantic feelings towards Y/n.

Would she work for the Dark Bosses?: No. She would rather work alone and only take on Y/n by herself and would ask her partner Chompers for assistance.

This is the best that I could find about her, but there should be more info about her when the game Street Devil comes out in a demo or the full release to see more of her in action.

Well, that's all for today. Hope you all have a good day and see you in the next chapter. Ciao~