Touya Sagami, among the fifteen humans born on the Moon and labeled "moonchildren," defied lethal odds as one of only two survivors into adulthood. The AI Seven’s experimental brain implants sustained his hormonal development in low gravity but remained embedded post-adolescence, threatening his life while enabling quantum communication with advanced AIs like Second Seven.

His slim physique, dark hair, and dark blue eyes accompany a signature wardrobe: green-and-white striped shirts, matching shoes, and a satchel housing his drone, Darkness Killer (Dakky). Post-timeskip attire shifts to a blue FiTsZ-branded shirt, later a green jacket layered over a black shirt with the same logo. Lunar gravity’s toll on his musculature forces reliance on a custom wheelchair for mobility in Earth-like gravity.

Initially, he nurses seething contempt for Earthlings, condemning their bias against space-born individuals and perceived neglect of lunar colonies. Rebellious acts—like hacking Dakky’s AI limiter—reflect his defiance. Self-imposed isolation fuels nihilism, dismissing gravity’s utility and tacitly endorsing eco-terrorist ideologies advocating mass population control.

Crises aboard the failing Anshin station and bonds with Earth-born peers gradually reshape his perspective. Reluctant collaboration with Taiyo, a UN-linked hacker, merges their drones Dakky and Bright into a unified tool, bridging divides. This growth culminates in his choice to venture to Earth, shedding nihilism to embrace human connection and new challenges.

A prodigious hacker, he exploits AI vulnerabilities to manipulate systems—from station controls to his own implants—averting disasters. Though initially resistant to physical therapy, he later pioneers survival strategies for space-born children, synthesizing quantum mechanics and AI insights gleaned from Second Seven. His journey traces a path from isolation to interdependence, marked by technical ingenuity and evolving resilience.