Honkai: Star Rail: Reborn as a Doomsday Beast and Captured by Herta

[Honkai: Star Rail fanfiction + Doomsday Beast + Herta + Single heroine + System progression + Adorably unexpected contrast + Power fantasy]

Xiao Yi was an A-rank survival expert in the wasteland of his previous life. After dying, he fell through a crack in imaginary space and was forcibly transformed by the "Abyssal Monster System" into the ultimate villain capable of destroying planets in the world of Honkai: Star Rail: the Doomsday Beast!

To make matters worse, before he could even hatch after being reborn, he was captured by the passing genius girl Herta and taken back to the space station laboratory.

He thought he would be able to punch Aeons and kick the Stellaron Hunters, only to discover he was currently the size of a palm. Xiao Yi tried to fight back, straining to unleash a Doomsday-level attack... only for Herta to flick him away with one finger and stuff him into a transparent petri dish.

"An Imaginary creation with a mind of its own? Now this is interesting." Herta's purple eyes gleamed with a fervent thirst for knowledge.

From then on, the mighty ultimate calamity became the number-one pet in Herta's laboratory. Forced to act cute, made to eat, and subjected to endless cuddles and hugs, his days became a humiliating routine.

Xiao Yi roared inwardly: I want to conquer the sea of stars! Not become a mascot!

The System coolly prompted: [Current form: hatchling. Combat power: 0.5 Hertas. Recommendation: lay low and grow]

Fine, then he'll lie low! He'll act soft and adorable like a pet on the surface while secretly devouring Imaginary Energy, evolving into his berserk form, dragonkin form, complete form... He'll rise from a cute mascot to an ultimate deity who strikes fear across the universe!