Humanity's Greatest Mecha Warrior Systemby Aoki_Aku

Him and her are reincarnated people( so they are mature, and don't have kid bodies because the nanomachines make them grew fast), I put it in spoiler because I don't know if they said at the start, but Im pretty sure they said it. While he keep cool head when Nico disappear you have to understand that he was one of the best warriors in his time, and need to keep cold head in a war, and the cyborg body at the start is like a human but made of metal but with more chapters Nico evolve to the body to be the texture, the color, and elasticity and all that like a human so it doesn't really matter, moreover Nico and Mc doesn't have s*x or something like that until the 700-800 if i remember well, moreover the goal of the story is become strong and then try to understand what happened in the past, because they get clues that they are in the same universe but a lot in the future, but is true that until middle (500 aprox)chapters is kinda like a slice novel but of war, but if you like mecha and all that is pretty good,anyway just saying

SPOILERS: There is two romances with main cast, Nico sets up Max with a girl for a bit of the story who is a researcher but that fizzles out due to different life styles. Max and Nico end up together with Nico being the one to make it happen