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 is a boy of average height with medium length black hair who wears glasses. For school, Osamu wears a blue suit top and gray bottoms traditional of Japanese high school students. When not in school or in Trigger mode, he usually wears a sweater and a striped scarf.
When in Trigger mode (C-Rank) Osamu gains an all-white suit with Border emblem patches on the shoulders with a long yellow stripe going down the middle of each sleeve. When in his B-Rank attire Osamu has on a blue jacket with a guard on his left shoulder. His left sleeve has a thick black stripe running through it, with a thinner, white stripe in the middle of the black one, and ending in the shoulder guard. On his shoulder guard, he has the Tamakoma Branch Symbol. His Unit's emblem is located on his left chest.
PersonalityEditOsamu is a very honest person, as noted by Yūma Kuga who has the ability to discern lies and is thus very trusting of Osamu. Osamu is very determined and courageous, always going out of his way to help others even if he puts himself in harm's way. He has a strong sense of justice. It is implied by Jin that his reason for joining Border was to help others (in particular Chika). On the other hand, Tachikawa labeled him a ruthless individual, using crafty strategies to win battles.
Osamu knows he has a limited talent for direct combat and that he is not nearly as proficient with his trigger as his teammates and other Border members. He recognizes his weakness and strives to become stronger.
Kazama's advice to fulfill his duties as a captain had an impact on Osamu since it allowed him to change his approach and make his team stronger rather than just focusing on himself. This change in thinking has allowed Osamu to think outside the box and strengthen his team by pursuing ideas such as deciding to add an additional member to his team, asking Jin to join his team, agreeing to allow a formerly hostile neighbor to be part of his team and finally using negotiation tactics such as controlling the flow of the conversation by implanting "agents" in a room, a tactic he learned from Eizō Netsuki when it was used against him in the press conference.
Not much of their relationship has been seen, but Kasumi initially disapproved of her son joining Border. After noticing nobody who visited Osamu said he should leave Border, and after watching his speech, she seemingly changed her mind. She also seems to believe Osamu and Chika's relationship is more than friendship, as she constantly tries pushing them together.
Rinji was Osamu's tutor and is Chika's older brother, who Osamu looks up to. He promised to Rinji that he'd protect Chika. After he disappeared, Osamu became Chika's guardian and tried joining Border to better protect her.
Osamu acts as the voice of reason for Yūma and teaches him about Earth's customs. Despite originally conflicting due to their different beliefs and upbringings, they grew to trust each other and became great friends with both willing to risk their lives to help each other.
Chika is the younger sister of Osamu's tutor, to whom he promised that he would protect her, which is part of the reason why he joined Border. He was the only person whom she trusted after the disappearance of her friend and brother, and before she joined Border. He is always encouraging her, and she has a lot of trust in him, too .
Jin saved Osamu from a Neighbor, after the latter tried to break into Border's HQ, and helped him join Border as a combatant. Jin is also one of the people who see potential in Osamu, always encouraging him to do his best. As a result, Osamu looks up to him.
Arashiyama became friends with Osamu after he and Yūma saved their school and all the students, including his siblings Saho and Fuku. He praised Osamu for his good work, rather than scolding him, despite Osamu breaking the rules of Border. He is always eager to help him.
Osamu has a lot of respect for Kitora, who originally scolded him for breaking Border's rules, but later saw how good he really is. She's always trying to outsmart him, but he doesn't really care. She seems to be interested in his growth. She also envies him for being Kyōsuke's student. He later asks her to train him to better fight with his low trion level. Despite her harshness and criticism towards Osamu, she does believe in Tamakoma 2's potential as later she acknowledged that if Tamakoma 2 was utilized properly they could easily score more points in rank wars. She is also the one to suggest and train Osamu to incorporate the Spider trigger to his fighting style, for which Osamu himself seems very grateful.
Kyōsuke is Osamu's teacher at Tamakoma, and thus is always encouraging him to fight with his full power. He considers Osamu weak but intelligent, encouraging him to become stronger and to fight offensively rather than defensively.
Usami is the operator for Osamu's team.
At first, Yōtarō thought that Osamu was weak, but he grew fond of Osamu, becoming enraged at how Border wanted to use him as a scapegoat.
Midorikawa initially felt jealous of Osamu's fame because of the rumor about his tie with Kazama and for being in Tamakoma with Jin. However, when Yūma beat him, he started to show respect towards Osamu and call him "senpai".
Mikumo asked Izumi to teach him composite bullets, and instead, he offered Osamu the chance to train with his teammate Yuiga.
Yuiga is an A-ranker by sponsorship that has a personality that is the opposite of Osamu's. However, they get along fine and often have mock battles so as to help Osamu out.
- (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" 
- 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.
- "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 and it's holstered on his right side. He also uses chopsticks with his left hand.
- He likes his parents' handmade 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 the Main during the match against Katori and Kakizaki Unit. 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 next match.
- During that rank battle, however, he again uses it at the same time as Raygust on one occasion, which should be impossible.