"Manhole" (マンホール, Manhōru, Tonari: 133) is the 92nd chapter of the One-Punch Man manga series.
The chapter starts with Saitama brushing his teeth, suiting up in his hero costume and heading out towards the battered streets. Meanwhile, Garou remains restrained by Gyoro Gyoro's psychic powers. Gyoro Gyoro comments on Garou's incomplete monster transformation bringing out his great potential but still lacking greatly. Gyoro Gyoro desires to elevate Garou into an even greater monster, not through psychics powers like Garou questions, but through a specialized monsterfication process. Gyoro Gyoro explains that in order to accelerate the growth process, the human must repeatably experience death in order to overwhelm the body and spirit.
This is a delicate balance as the human can easily succumb to death during the process and even successful candidates will stagnate due to low intelligence. The key ingredient needed is for the human to experience their very own personal hell. Garou says that it sounds like Gyoro Gyoro performed this process numerous times to which Gyoro Gyoro confirms on both humans and monster. While it is easy to turn humans into monsters, the process simply improves existing abilities the human has and has little to none prospect for further growth.
Some experiments Gyoro Gyoro performed to break this growth limit include, cannibalism, blood and cell transfusion, breeding, torture, inciting their anger and hatred and more. Garou stares on, grimly. From Gyoro Gyoro's experiments, the repeated experiences of death allows the person to explosively grow in strength and abilities. Despite this know-how, Gyoro Gyoro never managed to create a monster with a disaster level dragon except for one.
The scene cuts back to a woman wearing glasses approaching a silhouetted man. She states that the man has turned back on humanity and is going crazy. The scene changes again and the woman looks up towards the newly created Monster King Orochi. Gyoro Gyoro mentions that Garou has qualities greater that Orochi and through his battle with Royal Ripper and Bug God, Garou has broken through another wall of limits. Gyoro Gyoro offers Garou to join forces. Under Gyoro Gyoro's guidance, they will crush the heroes and Garou will attain the power to become the strongest monster.
Garou refuses but Gyoro Gyoro says he never had a choice. Gyoro Gyoro reassert Garou's powerlessness again by reminding him of his binding and her psychic powers dwarfing the witch sisters, Tatsumaki and Fubuki. Nevertheless, Garou begins to take a step as he is getting used to it. This time Gyoro Gyoro disciplines Garou with force as rocks are thrown at Garou. In doing so, a weakness is revealed in that Gyoro Gyoro can only perform one action at a time and Garou is freed from his binding.
Garou mocks Gyoro Gyoro and that by killing the brain behind the Monster Association, it will naturally collapse in itself. Orochi intervenes, grabbing Garou and pulling him down to eye level with Orochi. The stage reconstructs with Gyoro Gyoro's prodding and Garou begins to do battle. Orochi fires his horns at him, piercing Garou and leaving a visible round hole in his abdomen. Gyoro Gyoro comments on Orochi horn manipulation as his first discovery as a monster.
Garou defends himself with Water Stream Rock Smashing Fist and stays on the move, killing some monsters as he does so. Garou leaps to attack Orochi head on, but mouths within mouths open up in Orochi's jaw and almost bites down on him. Orochi transforms into a serpent-like being that seems to be a mixture of a hydra and tyrannosaurs rex. The reptilian heads fires a super-heated flame at Garou, incinerating the entire stage. A fist forms from snakes appendages and smacks down on Garou, sending him into a wall. Gyoro Gyoro calls for Garou to give up but he refuses, bragging about his status as a genius combatant. He acknowledges Orochi's strength, but claims that he is missing the primal terror that makes him a true monster.
Garou utilizes Abandonment and shifts into his fighting stance. Much to his surprise, Orochi copies his stance, and Gyoro Gyoro informs him that Orochi too is a "genius" in the same way Garou, having managed to adopt his style as they fought. The fight renews and this time the dragon appendages all utilize Water Stream Rock Smashing Fist. Garou is defeated. Gyoro Gyoro comments on Garou's lack of the bloodlust commonly found in monsters despite his intense wish to become one. As such, Gyoro Gyoro plans to thoroughly brainwash him into another ace of the Monster Association.
The chapter ends with Saitama looking down a manhole where he is sure he heard sounds from.