Heart Gear

Heart Gear is a humanoid machine cast in roughly human proportions. Antennas rise from its shoulders, and its head is molded into the shape of a heart complete with a visible, beating pulse.

The robot is engineered to obey its maker without question. Dr. Kuseno describes having given it what he calls a pleasant disposition, even as he handed it the grim assignment of wiping out humanity entirely.

Heart Gear enters the story once Bofoi denies being the architect of the robot invaders' chaos and pins the blame on Kuseno. Torn by inner conflict, Genos races to a laboratory almost against his own will and finds a screen bearing Kuseno's face beside a humanoid robot. Kuseno then confesses that he himself is the Rampaging Cyborg, having survived Blast's long-ago attack, which spared his brain, and having rebuilt himself endlessly since with an ever-growing cybernetic mind backed by copies of his own personality. He admits to stealing Bofoi's cyberization technology, once a classmate, to fuel his advances. At that point Heart Gear descends and is presented as the Ultimate Machine God, and Kuseno tells Genos that if he still means to be a hero, he must stop the machine.

No disaster level is officially assigned, yet its creator insists its combat power towers over the robot invader army and every other Machine God. Among its confirmed capabilities is flight, allowing it to hover in midair.