National Games Arena: I Picked up the First-Generation Mecha at the Beginning

Apocalypse AI destroys the world, and young adults around the world are transported into a secret realm. Each person has a mecha core, picks up trash, builds mechas, and plunders each other. Every 30 days, the National Games Arena opens - if you win, the resources of the Dragon Kingdom will be doubled; if you lose, alien beasts will overwhelm the territory and no grass will grow. Lu Jin, an old human who only knows how to repair machines. At the beginning, I picked up the broken first-generation mecha "Xingtian" that no one in the whole secret realm could repair. He can see through the weaknesses of all mechas at a glance, but he can't save his sister, Lu Yao, who is lying in the life-support cabin in the real world with only 41 days left. The source of life is in the ring. He built a mecha, fought battle after battle, and won national destiny for the Dragon Kingdom. From a scrap blacksmith who picked up garbage, to a warrior of the Dragon Kingdom. This battle will cost me my life!