Oc/Reader Works as a Detective in a Precinct In LA. (her personality is like Rosa from Brooklyn 99, but her backstory is different and she is not bisexual, And you can choose her race)

She is considered "the tough guy" and the "badass" in the Precinct.

Reader/Oc is scary, smart, secretive, and difficult to read. Most of the members of the precinct are frightened by her as she has shown Anger issues.

The Cops in the precinct know nothing about her and they don't get along at all.

Despite this behavior, she does show care to victims willing to sacrifice herself to save them. And doing what ever it takes to help them.

She meets the BAU when they get called in on a case.

For some reason she Bonds with Garcia when they team are on call with her. (You can choose different if you want)

She is very involved in the case and with her help they have a breakthrough and manage to find the unsub and save his victim.

Reader/Oc arrived first on her motercyle and finds the unsub about to kill his Victim.

She tackles him and then using her fits beating him up until he is unconcius. Then she comforts the victim promising that he will not be able to hurt them again.

Hotch and (You choose if Gideon is still here or it's Rossi) are very impressed and recommend for her to join the FBI academy and then apply to be in the BAU.

She does and she is the top Trainee in the Lot.

She Joins the BAU.

Her past is revealed when her Brother escapes a Ambulance after lethaly injuring himself in prison.

Her older half brother had Raped her from a Young age and when she Told her parents after She saw on the news that other girls who looked like her were being raped and killed.

Her brother was confronted by her parents and he killed them.

He kept her captive for days as he raped and tourtued her. 

Before police arrived and manged to arrest him.

He was jailed for life.

And he was always getting in contact with her so she moved from her town town in (You choose) and became a cop In LA.

(End game is Her and Spencer.)