Osamu Mikumo

This page is about the character. For other uses, see Osamu Mikumo (disambiguation).

"...It's nothing so noble. I just think... If I ran away from what I think I should do even once, then surely, I'd end up running away when it matters most. I know the kind of person I am. I'm not doing it for others. I do it for myself."

- Osamu Mikumo to Yūma Kuga about his reason to help others

Osamu Mikumo is one of the main characters of the manga and anime series World Trigger. He is a modest high schooler who had originally joined Border in hopes of protecting his friend Chika Amatori, but soon becomes the Captain and Shooter of Tamakoma Second.

Appearance
Anime=|-|Manga= Osamu is a boy of average height with medium length black hair and glasses. For school, Osamu wears a blue suit top and gray bottoms traditional of Japanese high school students. When not in school or his Trion body, he usually wears a sweater and a striped scarf.

When in Trigger mode as a C-Rank Agent, Osamu gained an all-white suit with Border emblem patches on the shoulders with a long yellow stripe going down the middle of each sleeve. In his B-rank attire Osamu has a blue jacket with a guard on the left shoulder containing the Tamakoma Branch emblem. His left sleeve has a thick black stripe running through it, with a thinner, white stripe in the middle of the black one ending in the shoulder guard. His Squad's emblem is located on his left chest.

Personality
Osamu is a very honest person, as noted by Yūma Kuga, who has the ability to discern lies. Highly determined and courageous, with a strong sense of justice, Osamu always goes out of his way to help others, even if it puts him in harm's way. It is implied by Jin that his reason for joining Border was to help others. From his side, Osamu doesn't believe his actions are particularly noble or benevolent; rather, he doubts his own drive on principle, and believes that if he ever compromises, he'll start running away from every situation, including ones that matter. This mentality leads Osamu to genuinely believe that his actions are selfish in nature.

Osamu is aware of his limited talent for direct combat and his inadequacies compared to his teammates, or other Border members, and strives to improve upon his weaknesses. Kei Tachikawa considers him a ruthless individual, as he uses crafty and opportunistic strategies to win battles. Kōji Oki notes that Osamu deals with setbacks with a level head, rarely panicking or hesitating in the face of adversity, even in situations with his life on the line, such as his gambit during the final act of the Second Large-Scale Invasion.

Sōya Kazama's advice that Osamu fulfill his duties as a captain had an impact on the Shooter, changing his approach to make his team stronger rather than focusing on himself. This change in thinking has allowed Osamu to think outside the box and strengthen his team through ambitious ideas such as asking Jin to join his team, agreeing to allow a formerly hostile Neighbor to ally with them, and using negotiation tactics such as controlling the flow of the conversation by implanting "agents" in a room, a skill he learned from Eizō Netsuki when it was used against him in the press conference after Aftokrator's Invasion.

Kasumi Mikumo
Not much of their relationship has been seen, but Kasumi initially disapproved of her son joining Border. After noticing how nobody who visited Osamu in the hospital after the Second Large-Scale Invasion discouraged his participation in Border and watching his speech during the press conference, she changed her mind. She states that he is free to make his own decisions in life, but she also guaranteed that she would forcibly drag him away from Border should he ever grow weary of it. She also seems to believe Osamu and Chika's relationship is more than friendship, and repeatedly tries to push them together.

Rinji Amatori
Rinji was Osamu's tutor and Chika's older brother, making him a person Osamu looked up to. He promised to Rinji to look after Chika, a task that Rinji explicitly entrusted him with before going missing through a Gate. Since then, Osamu took his role as Chika's guardian seriously, even joining Border in hopes of better protecting her. While he mostly aims for the Away Mission due to Chika's predilection to do so, Osamu has also expressed concern for Rinji's wellbeing and circumstances.

Yūma Kuga
Initially meeting him as a new classmate, Osamu was the first person Yūma grew to trust on Earth due to the former's honest nature, one that was greatly apparent to Yūma's through his Side Effect. Osamu would be the first people Yūma confided about his origin, and would later be grateful that Osamu was the first Border Agent he happened to meet. Choosing to trust him about maintaining secrecy and keeping a low-profile, Osamu would act as Yūma's voice of reason, teaching him the customs of Earth and Japan, helping him acclimatize to his new environment.

Yūma was puzzled by Osamu's kindness at first, but came to accept it as a part of his character. Yūma seems to draw parallels between Osamu's reckless altruism and the final act of his late father, Yūgo. As such, he doesn't fully understand where their drive to sacrifice themselves comes from, but hopes to understand it. It was partially out of concern that his indiscriminate kindness would get him killed that Yūma agreed to join his team on Border.

With time, the two would come to better understand each other and become great friends, with Yūma risking his life to aid Osamu during Aftokrator's Invasion; first by sending Replica to help him, and later by rushing there himself. In the aftermath of the invasion and the press conference, Osamu addressed Yūma as his "partner", further demonstrating how their friendship has developed over time.

As fellow members of Tamakoma Second, Osamu and Yūma rely on each other in battle, with Osamu placing great faith in Yūma's individual power, and Yūma trusting Osamu's strategies and judgments as Captain, best shown in how he hasn't contested any of Osamu's decisions till date. Yūma doesn't hold Osamu's lack of battle prowess against him in the slightest, having no reprimand for his failings in Round 4 of the B-Rank Wars. The duo would prove to be a powerful tag team, with some of Tamakoma Second's best strategies and victories relying on their coordination (such as their defeats of Kōtarō Suwa, Katori Squad, and most notably Masataka Ninomiya).

Chika Amatori
Chika is the younger sister of Osamu's tutor, who had Osamu promise to protect her in his absence, which was part of the reason he joined Border. He was the only person whom she trusted—specifically about her Side Effects and the fact she was targeted by Neighbors—after the disappearance of her friend and brother, at least before she joined Border. He is always encouraging her, and she places much trust in him, too. When Usami was asking for Chika's strengths, Osamu was able to quickly assess her strong points, indicating he knew her quite well even before they were teammates.

As Border Agents, Chika follows Osamu's orders as Captain, and places great faith in the strategies he enacts. For his part, Osamu (as well as Yūma), was quite concerned by the Chika's lack of self-worth and propensity for offering herself up as a sacrifice, which led him to explicitly order Chika to prioritise her own safety, even during the Rank Wars, which were entirely safe environments meant for training. Tamakoma Second's entire purpose is to support Chika's goal to go on the Away Mission and search for her brother and friend, a goal that Osamu and Yūma both endorse, even though Osamu was initially concerned when she decided to join Border.

Osamu's concern for Chika's wellbeing is reciprocated, as Chika felt incredibly guilty when Osamu was injured protecting her during the Second Large-Scale Invasion, and would constantly worry if she was holding her team back due to her inability to shoot people. According to Shūji Miwa, the problem wasn't Chika's resolve, but Osamu not having the heart to give her the order out of concern for her feelings. In the end, it was the sight of Osamu in danger that allowed Chika to overcome her block during the Final Round of the B-Rank Wars.

Yūichi Jin
Osamu first met Jin when the latter saved him from a Neighbor back during Osamu's break-in of Border HQ. Jin would help Osamu join Border as a combatant, something Osamu would gratefully reflect back on many times in the future. He recognized Jin immediately when he saw him again, and expressed relief that Jin remembered him as well. The former S-Rank agent has referred to Osamu as "Four Eyes" from the day they met.

Osamu holds Jin to generally high regard, looking up to him as a Border agent and admiring both his strength in battle and his ability to get things done through connections and natural charisma. In the anime, Osamu couldn't help but compare his present self against Jin, reinforcing the impact his rescue had on him, even after all that time. Osamu's admiration of Jin would eventually lead him to request the A-Rank agent to join Tamakoma Second.

From his side, Jin is always encouraging Osamu to do his best, and looks out for his wellbeing, giving up his Black Trigger to ensure Tamakoma Second could enlist, pulling multiple strings to ensure Osamu's survival of Aftokrator's Invasion, and later laying the groundwork for Hyuse's membership in Osamu's team. Jin is one of the few people who sees potential in Osamu, and places great faith in his ability to reach his goals, seen in how he entrusted Galopoula's communication bracelet to the Shooter with the confidence that he would clear the Expedition Selection Exam. As such, Jin is almost always in Osamu's corner, and although he couldn't take up his request to join Tamakoma Second, Jin maintains that he owes Yūma and Osamu for the aftermath of the invasion and Replica's sacrifice, intending to repay them in the future.

Kyōsuke Karasuma
Karasuma is Osamu's mentor at Tamakoma, responsible for his training and improvement. Although initially underwhelmed by Osamu's lack of combat ability, Karasuma nonetheless worked on helping him improve. Over their time as mentor and mentée, Karasuma came to grasp Osamu's character quite well, encouraging him to be more offensive in battle and later recommending him to be a Shooter instead of a Gunner after diagnosing him as "weak, but not stupid". Although not to the same level as Jin, Karasuma also believes in Osamu's potential, seeing worth where few others could in his matches against Sōya Kazama, and taking pride when his apprentice managed to force a draw against the no. 2 Attacker.

During the Second Large-Scale Invasion, Karasuma's concern over Osamu's safety was such that he tried to go against Jin's prediction and be the one to defeat Hyrein, thus averting the danger to Osamu. When this failed in spite of the All-Rounder's best efforts, the generally stoic Karasuma expressed uncharacteristic frustration.

Over the course of the B-Rank Wars, Karasuma would continue to guide and help Osamu as best as he could, such as by connecting him to Arashiyama to learn advanced Shooter techniques, helping him develop strategies by studying the logs, and later by emulating Masataka Ninomiya's trion levels and combat style in the virtual combat zone to help him prepare for Tamakoma Second's upcoming match.

Jun Arashiyama
Arashiyama became acquainted with Osamu after he saved the students of his school, which included his siblings Saho and Fuku. He praised Osamu for his good work rather than scolding him, in spite of Osamu breaking the rules of Border in that context. Arashiyama has stated that he owes Osamu a great deal when he came to support the Tamakoma Branch during the Black Trigger Capture Arc. He was also enthusiastic to teach him Shooter techniques in preparation for Round 4 of the B-Rank Wars.

Following Tamakoma Second's crushing defeat, Arashiyama was concerned that the match would have been a "bitter pill" for Osamu to swallow, recognizing its impact on the Shooter's psyche and self-esteem. Osamu would later agonize over his defeat on account of feeling guilt for having wasted the efforts of those that helped him, including Arashiyama.

Ai Kitora
Osamu respects Kitora for her superior skill and talent, and although the A-Rank ace originally chided him for breaking Border's rules and thought he was trying to draw attention to himself, she later saw how sincere he was, and even attempted to defend his actions in her report to Border's Upper Echelons. She is constantly trying to look better than Osamu, especially in front of their mentor, Karasuma. She also demands respect and recognition from him, but is surprised when he actually gives it.

In spite of her dismissal of his efforts and harsh criticism, Kitora is genuinely interested in Osamu's growth, and only scrutinizes his efforts from a position of understanding, as she doesn't want him to get invested in unrealistic goals. While she can relate to his struggles with low trion levels due to having once had the same problem, Kitora was hesitant to help Osamu as she believed inordinate kindness would only become a burden to someone with his sense of responsibility and gratitude, showing deep-rooted concern and a deeper understanding of Osamu's character, as her sentiment rang true given Osamu's guilt over his defeat in Round 4.

Upon further request, she suggested the Spider trigger to Osamu, along with tips for how to incorporate it into his strategies, which he would be extremely grateful for. After this, Kitora would take some shred of pride in his achievements, but also stated it was natural given Tamakoma Second's capabilities, showing her belief in the merit of Osamu's team, a sentiment that she held even during her earlier criticism.

Kōhei Izumi
Osamu approached Izumi on Arashiyama's referral, and requested to learn how to score on his own, and how to create composite bullets. Izumi seemed to appreciate the younger Shooter's ambition, and took up this request contingent on Osamu defeating Takeru Yuiga in one-on-one matches, and was even willing to cut the quota in half and teach Osamu while he was only partway to this goal, although the latter turned it down upon realizing where he stood. In spite of this, Izumi would continue to track Osamu's progress and follow up with him. As Izumi was the commentator for Round 5 of the B-Rank Wars, he openly hoped that Osamu would show him "something interesting" during the match.

Takeru Yuiga
Yuiga's personality can be seen as a polar opposite of Osamu's: entitled, self-important, and fundamentally cowardly. Despite this, they got along rather well when Osamu trained with him one-on-one. While this might be due to Yuiga's delight over finding someone weaker than him, it might also be due to Osamu's personality, which led to him to treat Yuiga with more respect than the Gunner had come to expect from his own teammates. According to Izumi, Yuiga was actually sad that Osamu wouldn't be "playing with him" anymore.

Quotes

 * (To Yūma) "Even though my chances of winning are slim, I still can't run away."
 * (To Yūma) "It's nothing so noble. I just think... If I ran away from what I think I should do even once, then surely, I'd end up running away when it matters most. I know the kind of person I am. I'm not doing it for others. I do it for myself."
 * "Forks in the road don't wait for us to choose. If I wait until all my ducks are in a row, I might never get anything done in my lifetime."
 * "I'm not a hero. I can't make anyone happy with any result. I can only do what I deem right with me not hating my choice at a later point."
 * "I'll get them back. Your family members that were taken by the neighbors... your friends... we'll get them back. You don't have to tell me about taking responsibility. It's the obvious thing to do."

Trivia

 * "Osamu," written with the kanji "修," means "discipline," which fits Osamu's personality. "Mikumo" (三雲) literally means "three clouds."
 * Osamu seems to be left-handed since he carries his sword in his left hand which is holstered on his right side. He also uses chopsticks with his left hand. During his coma-flashback in the hospital, he appears to fill out a bubble-in aptitude exam for Border using his left hand.
 * He likes his parents' homemade cooking and bridges.
 * According to Ashihara's Q&A, he likes his mother's handmade cream croquettes with her special white sauce the best.
 * He came 1st in the First Character Popularity Poll.
 * Osamu made a cameo on a special chapter of Saiki Kusuo no Ψ Nan.
 * Ōji's nickname for Osamu, "Ossam," might be a pun on "Ossan" (おっさん), which is short for "Ojīsan" (おじいさん), meaning "old man."
 * It is possible Osamu equipped Spider to the Sub instead of Main during the match against Katori and Kakizaki Squad. In fact, he is seen using it in conjunction with Raygust, which is equipped to the Main, eight times, and almost always with his non-dominant hand. However, he seems to have changed its placement again before his follow-up match.
 * During that rank war, however, he again uses it at the same time as Raygust on one occasion, which should be impossible.
 * Osamu is prone to feeling a heavy, anxiety-ridden sensation in his chest.