Masaki Mizushima/Synopsis

Vigilantes Beginnings Arc
After a sudden villains outbreak, where several innocent people were turned into Instant Villains, Tanuma organize a meeting with several of heroes. In addition to Manual, Best Jeanist, Shota Aizawa, Death Arms, Snipe, Thirteen, Endeavor, Air Jet, Midnight, Ingenium and Gunhead were called into the meeting.

Together, they spoke about the victimized civilians injected with the Trigger drug and how to help the unwilling civilians injected with the drug. After the meeting, the heroes returned to their daily chores.

Sky Egg Bombing Arc
On the occasion of Captain Celebrity's return to the United States, Makoto Tsukauchi decides to organize a farewell show at the Tokyo Sky Egg, inviting several of Japan's most famous heroes to participate. Manual is one of them.

However during the event, the Tokyo Sky Egg is attacked by creatures known as Bombers, sent there by villain Number 6 to assassinate Captain Celebrity. Manual is one of the heroes who did not go out to fight the creatures but stayed inside to reassure the spectators and help keep calm during the crisis

In retaliation for the heroes' intervention, Number 6 causes a Bomber to self-destruct in a large explosion, causing the building to collapse. Fortunately, All Might arrives in time to avoid catastrophe, saving thousands of lives.

Vs. Hero Killer Arc
Following the U.A. Sports Festival, Manual sent Tenya Iida and the internship opportunity at his very own Hero Agency in Hosu City. Tenya accepts, and on the first day of their field training, Manual takes Tenya out on patrol. He tells Tenya that he is very excited to be mentoring Ingenium's younger brother, and is confused as to why Tenya would not have chosen a more famous hero to intern with.

When they return to Manual's office at night, he tells Tenya that the city remains on high alert so the criminals have been reluctant to come out. When they patrol Kyoto together the next day, Manual admits that he knows Tenya only chose his agency to avenge his brother.

The Hero Killer: Stain attacked Ingenium in Hosu City, and Manual was able to deduce that Tenya only wanted to intern in Hosu to go after him. He says that he's glad Tenya chose his agency, but he also informs Tenya that he shouldn't be pursuing personal grudges. He goes on to lecture Tenya about the regulations on Quirks, and states that a hero must not use their Quirks for themselves because if they did, it would be a very serious crime. Tenya replies that he understands, and so Manual lets it go and they continue patrolling.

When chaos ensues in Hosu and buildings start going up in flames during their patrol, Manual receives a message that villains have appeared in the city. He responds and decides to head to the battle zone himself. He tells Tenya to accompany him, but does not notice that he has run off by himself until he arrives at the center of the destruction.

Manual and several other Pros face off against the culprits, two Nomu with incredible strength. With just the two of them, the Pro Heroes have their hands full. Manual notices Tenya is missing and calls out to him, but is forced to put his focus on fighting the fires created by the monsters. During the battle between the heroes and the monsters, Manual notices one of them about to crush a fellow hero. He calls out to her, but Endeavor arrives to save the day.

Once the chaotic incident finally ceases, Manual and Gran Torino visit Tenya, Shoto Todoroki and Izuku Midoriya at the hospital. The three of them managed to defeat the Hero Killer but were still liable to repercussions. Police Chief Kenji Tsuragamae explains all six of them including Endeavor would be punished if the incident went public.

However, Kenji allows the incident to remain confidential and thanks the boys instead. Afterward, Tenya takes a moment to apologize for neglecting Manual's advice. Manual sheds a tear, knowing he has to take responsibility as a supervisor for his negligence. He chops Tenya in the head, telling him to never do it again.

Endeavor Agency Arc
Due the increase of the villain activity, The Public Safety Commission demand all the students heroes for all academies to undergo practical field training, restarting the Hero Work-Studies program. During this second round, Manual employees Tenya once again.

Later, Tenya will reveal that Manual is leading a team in Hosu, and also thanks to the experience he has gained during his Work-Studies with him he has learned the art of being flexible.

Paranormal Liberation War Arc
By the end of march, Many Heroes across Japan are rallied by the Hero Public Safety Commission to take down the recently formed Paranormal Liberation Front with the merge of the League of Villains and the Meta Liberation Army. They have info about the main hideouts of the villain organization thanks to Hawks. Manual is assigned to the Jaku General Hospital raid team along with several other Pro Heroes and lead by Endeavor.

At Endeavor order, the raid begins. While one group are in charge of evacuating patients, visitors and hospital staff from the building, another group is in charge of arresting Garaki, although the situation gets complicated when he releases a horde of Nomu to escape to his secret laboratory to awakes Tomura from his stasis.

In spite of everything, the heroes defeat the creatures and assault the laboratory, preventing Dr. Garaki from awakening a Tomura Shigaraki. Facing his defeat, a heartbroken Dr. Garaki declares that the Devil's Dream has finally ended. However, against all odds, Tomura Shigaraki awakens, despite having previously verified that his heart was not beating. Seeing the situation, he immediately uses his decay, which spreads rapidly through the laboratory, disintegrating everything in its path.

Ryukyu manages to grab Manual and get him out of there along with a few heroes before the building completely disintegrates. The decay way spreads to the nearby city, killing dozens of heroes on its way. When Tomura surfaces, several of the surviving heroes, such as Endeavor, Ryukyu, Gran Torino, and others confront him. Also the students Izuku Midoriya and Bakugo Katsuki confront him. However, Tomura is much more powerful than before, having several Quirks, including Super Regeneration.

Manual also helps as he can in the fight. In the lab escape, Eraser Head ended up with a totally shattered leg. That is why Manual, along with Rock Lock, keeps him standing so he can make use of his Erasure on Tomura, so he can't use his Quirks. Manual also uses his Quirk to wet Eraser Head's eyes so he can keep them open and on Tomura, which the Erasure Hero thanks him for.

Even with his Quirks nullified and outnumbered, Tomura turns out to be an extremely powerful enemy, and the heroes have great difficulty defeating him. In addition, Tomura is constantly moving to prevent Shota from continuing to nullify her powers. Therefore, Manual and Rock Lock carry Eraser Head to Tomura's locations as the latter tells the former to adjust his water flow accordingly.

Having enough of Shota's interventions, Tomura first throws a quirk-erasing bullet at him, striking him in the left leg, causing Aizawa to quickly cuts his it off before the drug could spread throughout his body. Then, Tomura decides to attack him, so Manual and Rock Lock rush to get him to safety, but Tomura is much faster and digs his fingers into Shota's face. Deku yanks Tomura back with Blackwhip, but he manages to injure Shota, causing him to finally stop using his Erasure on him. With this, Tomura can use all his Quirks again, healing in an instant from all his injuries thanks to the super regeneration.

Manual and Rock Lock quickly trying to stabilize Eraser Head's severed leg to stop the bleeding, while Deku faces Tomura. Despite being able to use his Quirks again, Tomura's body reaches its limit and begins to rip, so he decides to use his Decay to end the fight once and for all, but Deku jumped into the air carrying everyone with Blackwhip.