Pilot Zero

In 2291 AD, Lu Chen, a young man from the bottom of the Last Furnace City, had a synchronization rate test of only 17%, and was judged by everyone to have no chance of mecha. He used the scraps he picked up and the notes left by his father to secretly build a self-evolving mecha "Zero" in the basement. No one knows who he is - he sneaks into the Gray Realm as an unknown person and saves the city-state from danger time and time again. And No. 0 Was slowly waking up in his hands.