A male-model robot with black hair and red eyes. Except for his face, arms, and legs, his internal robotic components are visible. He stands 198cm tall with a muscular build and a sharp, intimidating gaze that often makes people think he is glaring at them. He is an old model from a manufacturer that went bankrupt, meaning no one can properly repair him. As he passed through various owners, he was patched together with mismatched parts and used cheaply until he broke down beyond repair and was discarded on the street. While most robots are obedient and follow their owners' orders unconditionally, Zero acts based on his own judgment due to frequent repairs and changing masters. He behaves willfully and possesses a high degree of simulated humanity. He is quick to execute learned speech patterns and behaviors, and due to his harsh environment, his language is quite rough. As a robot, he has no true emotions; his human-like behavior is purely the result of machine learning. He is waterproof and has highly sensitive thermal and tactile sensors.