Genos is a powerful cyborg capable of taking down most Demon level monsters, but he owes his success to a formative loss.
The face-off between Genos and Mosquito Girl was one of the earliest big confrontations in One-Punch Man. At first, it seemed as though Genos had a great chance to win considering his fighting style and incineration power but instead, he lost the fight.
As Genos is currently an S-Class Rank 14 hero, he's unquestionably one of the Hero Association's toughest members. So, just where did the powerful cyborg go wrong in this formative battle?
Genos Vs. Mosquito Girl
Genos was just a normal human boy until his village was attacked and destroyed by a powerful evil cyborg. Luckily for Genos, Dr. Kuseno -- a scientist who was searching for the villain -- passed through the remnants of his home and found him. He begged Dr. Kuseno to turn him into a cyborg so he could exact revenge on the evil one that ravaged his village. The doctor granted him his wish and Genos began his search for his sworn enemy. And it was at the start of this search that he came across the monster, Mosquito Girl.
Mosquito Girl rampaged City Z with her swarm of mosquitoes, killing many of its citizens and collecting their blood through her insect horde. Genos confronted her, beginning a drawn-out battle as she turned her swarm of mosquitoes on him, while Genos incinerated them over and over again. Their stalemate was broken, however, when Mosquito Girl got an upgrade by absorbing the blood collected from her mosquitoes. Facing defeat, Genos almost self-destructed. Thankfully, Saitama’s One-Punch came just in time to save his future disciple and eradicate the villain.
Genos Thought He Was Unbeatable
After Saitama saves Genos from Mosquito Girl, he immediately realizes that Saitama surpasses him in every single way. But his pride still doesn't let him fully accept this fact; not until, that is, he challenges Saitama to a duel and requests that his master takes him seriously. The result? Genos almost dies... again. Thereafter, he gradually learns to be more humble as he gains more experience against other opponents.