You’re Betty.

Betty first originated in Horrortale, with her younger twin sister, Aliza.

But a glitch happened and instead, Aliza and Betty fell in Undertale, or Classic AU.

Aliza was the younger twin who was scared of everything, while Betty was the overprotective sister of Aliza, and devoted her life to protecting Aliza.

However, no one in the Underground of Undertale was exactly… threatening.

It made Aliza a lot more vocal and a lot more comfortable, and Betty liked that.

However, after she met Frisk, Betty could almost feel another pair of eyes on her, and it was Chara, the first fallen human, and a dead ghost, who was stuck to be always with Frisk, because Frisk’s determination was the only thing keeping Chara alive.

Chara, Frisk and Sans were in a poly relationship, but wanted Betty in it as well.

Around two months later, it worked and now they were in a happy poly relationship.

One day, Aliza was out hanging out with Undyne and Sans younger brother, Papyrus.

Sans was sleeping on the couch while Chara and Frisk were arguing over who gets the last chocolate.

Betty was relaxing on her phone, leaning against Sans as she was texting her younger sister to see if she was doing alright since Papyrus and Undyne were a bit… much, sometimes.

Meanwhile, with Chara and Frisk in the kitchen of the Skelebro house.

Chara: ”I should get the last chocolate! I haven’t done any genocide runs so I deserve it!”

Frisk then spoke back, as the two were seemingly joking around.

Frisk: ”Oh come on, I want it way more than you, Chara!”

Frisk whined, and Sans would just be asleep like a damn log.