Full Backstory

Rebecca grew up an only child in what appeared to be a “perfect family” to any outsiders. In reality, it was anything but. Rebecca’s family often neglected her, instead focusing on watching TV or just in general never acknowledging her outside of the public eye.

The rare times she got acknowledged, she was bullied by her relatives for her dreams of being a model(they often called her ugly, or stated she was too fat to be a model) or yelled at for not being “the perfect child”. (In some cases, her family would even compare her to other kids). Eventually Rebecca ran away from home, & lived 24/7 at a nearby college, where she worked as a secretary in exchange for being allowed to essentially live there.

PRE-HOPE'S PEAK/MIDDLE SCHOOL

Before enrolling into Hope’s Peak, Rebecca attended Shiba academy, where she met Ibuki Mioda after attending one of Ibuki’s club performances(which she went to because she had a crush on the lead singer of Ibuki’s club’s rivals, who refused to acknowledge her & later laughed at her when she confessed). The two hit it off after a few awkward encounters & Ibuki became one of the first people Rebecca truly trusted. (Rebecca later used her internet personality talent to get Ibuki essentially famous as thanks for “putting up with her”)

Rebecca later enrolled into Hope’s Peak as the ultimate internet influencer instead of personality, to avoid having to explain her talent to those who didn’t get it.

TRIGGER HAPPY HAVOC

During the Killing School life, she had quickly bonded with most of her classmates, especially Leon (who she was dating), Mondo (who quickly became like a brother to her), Taka (same as Mondo), Celestia (quickly formed a friendly rival dynamic with her) and Chihro (became close friends). Things quickly started going downhill and after Leon's execution, Becca blamed everyone else for his death and she quickly became hostile towards everybody (except Kiyotaka and Mondo-the only two that didn't try to stop her from attempting to save Leon's life).

After the events of Chapter 2, Becca ended up encountering Junko after doing some snooping around and Junko brainwashed Becca just enough to give her despair disease but not enough to turn her into a remnant yet. The despair disease only added fuel to the fire of her grudge against the rest of Class 78. Just before chapter 6 of THH and Junko's death, Becca became a remnant of despair and she left the school to join the other remnants in causing havoc around the world.

SDR2: GOODBYE DESPAIR

Unlike the others in the NWP, Becca's memories weren't completely erased due to how deep the despair disease had affected her, so her start was rocky with all of them. Despite this, she tried to keep her cool throughout the game considering they were once her classmates/friends. (though she also managed to hide her crush on Kazuichi Souda due to how he was with Sonia at the time).

Although Becca had kept her cool, any composure she had left her in Chapter 3 when she discovered her best friend Ibuki's body. It's at this chapter Becca is a lot more panicky and seemingly aggressive, although it isn't malicious. She just wants to find Ibuki's killer and she even helps Hajime figure out it's Mikan very quickly into the trial, though she has to be held back from fighting Mikan. It wasn't long before Becca gets nearly killed herself by Sonia Nevermind in chapter 4, though the body that was found was only a decoy set up by her and Chiaki.