Planet Clearance Strategy: Upgrade! Level up Alone!

In this world, everyone is born bound to a cassette. The cassette determines the level and abilities. The level is inherently locked and remains unchanged for life. Want to become stronger? Buy from PLAY company. Those who can't afford it will always stay at the bottom. Zero is the bottom one. She had no cassette, and the test report was stamped with the word "empty shell." She had been picking up trash on Seventh Street for three years. The only person protecting her is Thirteen, a short-haired girl whose cassette is locked at level thirteen, with two skills - shield and healing. Not strong enough, but he can stand in front of Zero every time. Until Zero dug out a blank cassette from the trash heap, the size of a palm, with a "0" engraved on the back. At the moment of binding, white light exploded - level 0, 9 skill slots, not under the jurisdiction of PLAY Company. The highest level 100 cassette in the world only has 6 skill slots. Her cassette is level zero, but has 9 empty slots. If you want to become stronger, you have to rely on "points": fight, break through, and win. Earn bit by bit to add attributes, unlock skills, and break through levels. She wants to become stronger from scratch. Not for anything else, just to one day no longer wait to be protected. But what she didn't know was that the very existence of this cassette was a crack in the foundation of PLAY's dominance. When more and more people discover that they can grow, the myth of "insurmountable natural class" will be shattered. Passionate, rebellious, and side by side at the bottom - an empty-shell girl, fighting from zero to level 100.