Betterman

Keita Aono is a typical high schooler who enjoys talking with his friends about military tech and the girls in their class. One day, he's thrilled to see a new transfer student-his childhood friend, Hinoki Sai. When Keita tries to reconnect with her after school, he stumbles into Bottom World, an abandoned underground amusement park shut down after a mysterious disaster. While exploring, Keita discovers Hinoki inside a strange robot. She's working for Akamatsu Industries, a company partnered with the shadowy group Mode Warp to investigate bizarre outbreaks of violence around the world. After climbing into the robot with her, the two fight off the park's attractions, which have somehow turned hostile. Just as escape seems impossible, a man with shape-shifting abilities-known as "Betterman"-appears to help them. Now caught in a battle against an unknown enemy called "Algernon," Keita joins Akamatsu Industries, facing dangers he never imagined and technology he can barely comprehend.