Death Arms/Synopsis

Vigilantes Beginnings Arc
Death Arms is in Naruhata when he receives a call for backup from detective Naomasa. Without anyone knowing, the villain Kuin Hachisuka used her Queen Bee Quirk to inject Trigger into innocent civilians, causing an Instant Villains Outbreak. Death Arms and other heroes rush to the place of the outbreak and quickly they suppress the outbreak.

A few days later, Death Arms is called into a meeting at the police station with several of the heroes who also had participated in suppressing the outbreak like Eraser Head, Endeavor, Midnight, Ingenium and more. Once in the meeting room, detective Eizo Tanuma informs them that the Instant Villains they had defeated are unwilling civilians who were injected with Trigger by someone. The officer explains that the people in question were more victims than they were villains.

Once the meeting is over, the police station is attacked by the Suicide Bomber. Death Arms and other heroes prepare to defeat him before he hurts someone, but the villain is quickly defeated by Midnight and Eraser Head. Since everything has ended well, Death Arms leaves to returns to his duties.

Vs. Queen Bee Arc
The Marukane Department Store decides to hold an event about the Naruhata neighborhood, and they wanted appearances from hero involved in the recents outbreaks of villains. Death Arms is one of those who accepts the invitation. Except for a sudden blackout, the event proceeds without incident.

Sky Egg Arc
Death Arms accepts Makoto Tsukauchi's invitation to participate in the farewell show dedicated to Captain Celebrity at the Tokyo Sky Egg on the occasion of his return to the United States.

However, the event is interrupted when the Tokyo Sky Egg is attacked by creatures known as Bombers sent by the villain Number 6. The villain wants to kill Captain Celebrity, and for this, he planned the attack carefully. He orders one of his bombers to self-destruct to seriously damage the building, forcing Captain Celebrity to hold it to prevent its collapse, but leaving him defenseless against the attack of the creatures. He also makes another creature cut off communications with the outside.

In one of the rooms of the Sky Egg, the heroes and show staff discuss the situation. Death Arms is shocked after realizing how meticulous that terrorist attack is. The heroes decide to organize in two groups: one group goes outside and confronts the enemies, while another group helps the show staff to look after the spectators. Death Arms is one of the heroes who stayed inside to protect the spectators.

Thanks to Koichi was protecting Captain Celebrity, the heroes manage to arrive in time to help and defeats the Bombers. Number 6, who was watching everything on a rooftop, sees that his plan is about to fail because of the heroes' intervention so, in retaliation, he orders the last Bomber to self-destruct in a large explosion, causing the building to collapse. Fortunately, All Might arrives in time and manages save everybody life.

Entrance Exam Arc
Death Arms guides civilians out of the area while other heroes are fighting a Giant Villain.

Later on, Death Arms is among the heroes who are trying to stop the Sludge Villain who is controlling Katsuki Bakugo but he cannot do anything since the villain is too fluid. None of the heroes who are present can do something against the villain and Death Arms clenches his fist in anger. As he and the other heroes wait for a hero who is able to hurt the villain, Izuku Midoriya tries to help Katsuki.

Death Arms tries to stop him but Izuku does not listen to him. All of the Heroes then try to help him, but before they can do anything, All Might defeats the villain with one attack. Death Arms and the other heroes then clean the area. He later scolds Izuku for his actions since he could have been killed.

U.A. Sports Festival Arc
Having been assigned as security, Death Arms, Kamui Woods, and Mt. Lady are seen outside U.A. High School's Sports Festival Stadium. Kamui Woods and Death Arms originally wanted to scout for talented individuals but they are not able to do that because of the guard duty.

During the obstacle course of the festival, Death Arms spots Izuku Midoriya, the young man who purposely got himself involved with a villain and was amazed by his progress.

Later, after the rules of the Cavalry Battle have been explained, Death Arms, Kamui Woods, and Mt. Lady are in the break room and start discussing the U.A. Sports Festival. Death Arms says that the Sports Festival is all about preparing the young heroes for the real world of heroes and that the Obstacle Race was a way of showing that you need to kick down others to show what you are able to do. Mt. Lady, after mentioning that she feels bad about having done that to Kamui Woods, mentions that Heroes need to work together in order to accomplish a goal and the Cavalry Battle is a good representation of that.

Vs. Hero Killer Arc
Kyoka Jiro chooses to go with Death Arms for her internship. The hero works out Kyoka hard in the field. He makes her run during patrol and she barely keeps up with him. Kyoka thinks to herself how much harder her training is compared to school.

Later, Kyoka helps Death Arms rescue civilians from a hostage situation. She uses her Quirk to figure out how many hostages were taken. Kyoka escorts them both to safety after Death Arms rushes in.

Pro Hero Arc
Death Arms attends together with Mt. Lady to the Hero Billboard Chart JP, where Kamui Woods placed 7th. After Mt. Lady was interviewed, she cried as she ran to Death Arms for comfort about Kamui receiving recognition. He remarked that she was amazing in her own right.

Paranormal Liberation War Arc
After months of investigation, the Hero Public Safety Commission organize an operation to take all the members and associates of the Paranormal Liberation Front down at once. Two large forces of heroes are organized to raid the main bases of the villain organization, while other heroes are dedicated to arresting members who are in other places. Death Arms is one of those tasked with arresting PLF spies among the Pro Heroes.

All this was carried out with the greatest secrecy, to the point that Slidin' Go, one of these traitor heroes, is completely dumbfounded when he sees that there there aren't any Heroes around, wondering whats going on. He's suddenly captured by Death Arms, calling him out on his true allegiance as he gleefully explains that the PLF loyalists were the only ones who didn't know the truth.

Dark Hero Arc
After the results of the Paranormal Liberation War, many heroes have died or retired due to the intense collateral damage caused by Gigantomachia and Tomura Shigaraki. Death Arms attempted to continue fighting to help, but unfortunately, due to the public's harsh and at times, unbearable criticism of the Heroes, he admitted he could not handle the role anymore, and retired from the hero occupation.

U.A. Traitor Arc
He is later seen among the crowd of evacuees at U.A., watching Class 1-A say their goodbyes before they leave U.A. in preparation for the Final War.

Final War Arc
Death Arms continues to stay with the evacuees, as they are being transported through the Underground Evacuation System beneath U.A. During this time he watches the live broadcasts of the battles between the Heroes and the Villains, including Izuku's fight against Tomura, and the Heroes fighting All For One. Just then, the moving segments suddenly stop as the lights also go out, causing the civilians to worry.

As it turns out, one of All For One's sleeper agents within is using his Quirk to continue jamming the system, which Gunhead finds and gives chase. Elsewhere, parts of the blocks begin to break apart, as the hero students within act to defend the civilians from being crushed. However to their surprise, Death Arms appears and saves them by catching the large block of falling debris. He states that he knows that what happened before is bound to happen again, but thinking about Izuku and his first encounter with him, he says his body took action all on its own.