Art by peachiesheepie on Twitter

Megaton Rex (real name Genevieve ‘‘Ginny’’ Yeager)
Age: 24
Average Weight: 6300 Tons
Height: 350' +
Species: Kaiju
Sexuality: Asexual, Biromantic
Employment: Defender of Overland
Likes: Cake, Space, Baking and Cooking, Hugs
Dislikes: Tight Spaces, The Stares, Accidentally Turning Into A Kaiju, Having Fights With Her Mom
Bio: Ginny was born when a blue alien goo creature whose name can't be pronounced (who would later adopt the name Charlie Yeager and the form of an Iguana) and her mom (Catherine Yeager, née Biggs) melded mind-and-body for the first time. Catherine was unaware of the pregnancy at the time, but a rushed marriage covered it up. Ginny was always bigger than most other kids, soon growing to adult size and only slowing down when she entered her twenties. Her parents assumed it was likely because of her father's odd DNA and were never worried until her first day of Middle School. There, she was bullied excessively and transformed into Megaton Rex, a green colossus that was scared and confused. One military attack later, which cost Megaton Rex one of her horns and gave Ginny a notched ear, Catherine realized the monster she'd attacked was her daughter and lied to her superiors to cover for her. Charlie since figured it that leftover DNA from his previous host, a colossal creature not unlike Ginny's new form, had slipped within her chemical makeup. Ever since, when Ginny's emotions run out of control or she gets too hungry, she transforms into the titan known as Megaton Rex. She then spent most of her teenage years fighting back her own mother's MODU military force as a means to keep the cover, straining their relationship. Still, it was during those years she met her best friends, Kristof Vouten and Abby Benson, and that she got employed by Starlight Bakery, whose owner Dellie helped her get in contact with her mentor, Debbie Thorne, CEO of Triple S Sweets. All these people know her secret, much to her mother's chagrin.
Things changed for the better for Ginny, however, when she defeated the monster Poyzon, another kaiju born of scientific tampering and government conspiracy. Ever since that day, she's been viewed as a hero to the town as an alien force tries to take it over. She keeps her secret tight nonetheless but now there's a much wider group of people who know: her mother broke off her ties with the government and reassigned MODU as a task force to help Megaton Rex fight evildoers, sharing the knowledge of her daughter's secret with her troops to prove both that she had faith in them and that she had faith in Ginny. So look out, world, here comes Megaton Rex!