Need help with getting my story started.

Sorry if this is not to well explained.

Team SSFR (Saffron) The character is Radia Rosavelle. Allusion is Lucifer King of hell. And she also has a Inspiration of Granblue Fantasy Belial with her personality a bit.
This is AU but I want to try to keep it fitting to cannon power level and

I already got her pretty worked out. But I will give a short run over at the bottom just in case any one ask.

The main part I was to link to Lucifer is the fall from heaven or in this case fall from good or of herself. Seeing the world as black and white where being good is how one dies. Do what you must to live, easy power and fear to keep one safe. But I don't want her to be pure evil. Like I plan to give her a soft place for children. And even more so if there poor or living for pure survival. She would end up in a huntsman school to learn to fight other humans and grimm in a control place. This would be the place the makes her question herself. And no she will not become good. Just make different choice in what she fights for.

I was thinking of having her be sold off to slaver or something by her blood family that disliked her from just being another mouth to feed.
Or she could have been thrown out and left behind and found on the streets.

I am meaning to start work on a side oc that would be the main guy that train her to fight and manipulate. But also the one the pulls her more into the darkness she made around her. The idea was that her semblance was handy for getting information. This semblance and his words would make her believe that she was made to bring pain. Punish people that cross them.

Short Profile:

Radia color is Radioactive element like Radium. and it most connected with green. She is also female and a Snake Faunus. A Western green mamba.
She has a weapon too call Serpent's Kiss: A cane that tuns into a sword then a whip that send dust down a small dust tube in the wire.
Her Semblance is called Resonance. In short with a touch she can send her aura into another like a poison that hijacks the sensory pathways to incase one whole body Feeling to physical stimuli, sense of sound, taste, pressure and thermal sensitivity and so on. This effect can be really weak or strong base on how much aura she willing to burn up. High aura cost.

Limits:
The effects and time she can use it completely depend on the amount of aura she uses.
Amplification has a strong aura drain. Must make physical contact or run her aura down her weapon to activate.
She can’t lessen the effect. Only make it stronger.