Kuseno-hakase

Kuseno is calm, kind, pragmatic, and deeply concerned about Genos's tendency to treat his own body as disposable. He willingly equips Genos with stronger weapons but repeatedly reminds him that survival matters more than revenge.

He possesses a dry sense of humor and can engage comfortably with Saitama despite having little firsthand understanding of how extraordinary Saitama is.

Kuseno also supports Genos's apprenticeship. Rather than becoming jealous of another mentor's influence, he recognizes that Saitama has given Genos emotional stability that technology alone could not provide.

Kuseno is a brilliant scientist specializing in robotics, cybernetics, weapons engineering, artificial limbs, and energy systems.

He created most of Genos's combat body and repeatedly rebuilds it after severe destruction. Each new configuration responds to weaknesses exposed in previous battles, producing systems optimized for greater speed, durability, firepower, or short-duration maximum output.

Kuseno also uses automated drones capable of recovering Genos's damaged components from battlefields and transporting them back for repair.

Although not normally a frontline fighter, he possesses advanced defensive technology and combat-capable machinery for protecting his laboratory.

Kuseno enters Genos's history after the destruction of the boy's hometown. Genos asks him to perform the cybernetic surgery that will allow him to pursue the rogue cyborg responsible.

Throughout the series, Genos periodically returns to Kuseno after major battles. These visits track his growth through increasingly powerful sets of arms, cores, sensors, and armor.

Saitama eventually meets Kuseno and is surprised by the level of technical support behind Genos's body. Kuseno, in turn, becomes aware of Saitama primarily through Genos's enthusiastic descriptions.

The mystery surrounding the rampaging cyborg remains central to Kuseno and Genos's shared history, and the manga has not yet fully resolved every question surrounding that event.

Genos is Kuseno's patient, protégé, and closest established relationship. Kuseno transforms him into a cyborg and continually repairs and upgrades his body.

Saitama becomes familiar to Kuseno through Genos's admiration and later visits the laboratory personally.

Bofoi becomes relevant to Genos's investigation because of suspicions surrounding advanced robotics, although the manga has not conclusively established that Bofoi created the rampaging cyborg.