I Have a Mech Warrior

Humanity has entered the post-era - the mecha era, where computer technology has evolved and humans and mechas coexist. The mecha system created by humans "lost". After the system gained independent consciousness, it gradually lost control and became extreme. It developed a strong desire to rule. Before the creator died, he put all his hopes in a new mecha system called "Light", hoping that one day, someone could use it to stop "Lost" from his desire to dominate mankind. It wasn't until a thousand years later that a wanderer in the wilderness encountered "light"...