That's still writing tho...
Her parents died in [Insert a battle name here i haven't named yet lol]
and she was kidnapped and got send to a science lab
and there some sort of Crazy Doctor do some experiments on her for 100 (they did it in an abandoned place and you cannot age there)
She felt the pain that's worse then getting erased from Existence and non-existence
and specie type and her Reality, Existence got disorted
and after the experiment succeeded
He abandoned her in the INEXISTENT VOID
and she got tortured by some sort of unkillable creatures that live there
(In INEXISTENT VOID you cannot age)
and she has suffered for 1M years
Her organs and realities got ripped apart and they played her as a toy(also time is different there 1M = 10 years)
But some travellers from Undercrystallized AU
travelled across that void and they accidently dropped some Paramount-Ultra-Nitro powered crystal there.
So she tried to escape using them and she succeeded
but still on the surface, she was hated by everyone
And that gave her like ''trust issues''
she use her hatred power for fighting
And if she see some sort of lab that do some experiments on kids, she destroyes them and send the kids to "Undertale AU: Ultra-Nitro system (it is safe there)
and bc of her actions, the Executionverse's (An Evil verse which took over Elementverse) goverment announced that she's a 10 stars villain (like team clawfist)
(man i think went too far, Computer: yup you did)