Osamu Trion

Osamu's trion

Low Trion Level: Osamu has been shown to have a low amount of trion, it was stated by Yūma that Osamu would need three times his amount of trion to attract neighbors. It was stated by Replica and Kyōsuke Karasuma that his trion was weak, he even showed disbelief that Osamu was a B-Rank agent not knowing that Osamu was only able to acquire B-Rank status mostly due to Yūma's efforts. 


Osamu's defining trait is his high strategic and tactical intelligence, being praised by top-tier personnel such as Kazama.[1] He was able to outwit experienced opponents like Hairein and prevent the latter from achieving his ultimate goal, capturing Chika.[2]Further more Osamu can use advanced negotiation tactics such as implanting "agents" to control the flow of conversation a tactic he picked up from Eizo Netsuki when he used it against Osamu in the press conference.


Osamu Mikumo's Triggers
Type: White trion Normal Raygust
Osamu Raygust
Classification: AT Attacker
Osamu's main Trigger, which he chose when joining Border. It is a defensive Trigger, it has low strength but high durability, and is capable of shapeshifting. When he got promoted to B Class, he got a new one with a significant strength difference compared to his original C-Class Trigger, as Osamu was able to easily defeat a Vander.[3] When activated it takes the form of a large energy sword, but also has a blade better suited for combat and a shield as default modes. He was first seen using it in chapter 1 (episode 1 in the anime), while the blade and shield modes were first seen in chapters 5 and 12 (episodes 3 and 6 in the anime), respectively.

Type: White trion Normal Asteroid
Osamu Asteroid
Classification: GU Shooter
Asteroid is Osamu's ranged Trigger. He generally divides the trion cube in 27 pieces, but he has also fired it whole to maximize his output. His bullets are not very powerful due to his low amount of trion, although they can still effortlessly damage a trion body. When fighting alongside his teammates, he uses them to create disturbances and control the position of the opponent, using his excellent strategic abilities. He is also capable of reprogramming the Trigger's parameters to adapt to the situation. His skill was originally very poor, but after training under numerous A-Rank agents, his accuracy improved and he learned to scatter his bullets to increase hit probability at short range and attack from multiple directions at once, as well as to delay his shots in order to catch the target unawares after luring them in position. Osamu was first seen using Asteroid in chapter 12 (episode 6 in the anime).[3]

Slow Buckshot (低速散弾(ていそくさんだん) Teisoku Sandan?):[4] Osamu scatters numerous, small rounds of Asteroid bullets around himself, making it difficult for the enemy to maneuver or attack without coming in contact with these bullets. The power/range/speed ratio is 70/29.9/01.[5]

Type: White trion Normal Thruster
Osamu Thruster 2
Classification: AT Attacker
Osamu utilizes Thruster chiefly to increase the speed of his slashes with Raygust,[6] as well as to rapidly close in on the opponent.[7] He is also capable of using it to dodge,[8] throw Raygust in Blade Mode at the enemy[9] and to push an opponent in a favorable position with his Attacker Trigger in Shield Mode.[10] Osamu was first seen using Thruster in chapter 12 (episode 6 in the anime).

Shield Charge (シールド突撃(チャージ) Shīrudo Chāji?): Osamu activates Thruster while Raygust is in Shield Mode in order to ram into the target at high speed, pushing them back.[10] By prolonging its duration, this technique can be used to forcibly relocate an opponent.[11]

Type: White trion Normal Shield
Osamu Shield
Classification: Defense Defense
Border's default shield trigger. Since Raygust already has a shield mode, Osamu doesn't usually use it. He was first seen using it in chapter 69 (episode 31 in the anime).

Type: White trion Normal Spider
Mikumo Red Wires
Classification: OP Optional
Due to the low trion consumption of this Trigger, its versatility in the hands of a good strategist, and the low amount of skill, practice and accuracy necessary to use it, Osamu regards Spider as a near perfect weapon for him.[12] His primary tactic consists in setting countless wires between buildings (or other structures) in wide areas of the map. Since the wires' color can be adjusted to make it very hard for enemies to spot,[13] those areas become as disadvantageous to the enemy as they are advantageous to his unit.[14] In fact, this application of the Trigger makes full use of his teammates' abilities,[15] boosting Yūma's agility[15] while relying on Chika's Lead Bullet sniping to prevent the wires from being cut down.[16] They can also force enemies into the wire zones by having her shoot down other buildings with Ibis.[17] The wire zones are beneficial to Osamu himself as well, enabling him to slow down whole units with minimal assistance from Chika.[18] Since the opponent is hindered by the wires and must constantly watch out for them, whereas he can devote his undivided attention to combat alone, Osamu can score points on his own, and since the wires will keep supporting his allies even if he should bail out, he can fight without hesitation.[19] As a matter of fact, Spider allows him to be useful to his team without fighting at all. An application of Spider that was not suggested to him by Ai Kitora is the creation of highly visible wires, which are generally red in color, and the gradation of the others: by summoning red wires when the enemies come too close, they will inevitably be less alert to the ones around them.[20] This technique is more complex than it seems at first glance, because some of the normal wires are set to be more visible than others,[21] which further disorients the enemy and prevents them from understanding why they tripped despite being careful.[22] However, it will fail if there aren't enough wires in Osamu's vicinity.[23] He can also anchor an enemy to an object by shooting the hooks directly at them, restraining them briefly.[24] Osamu starts training with Spider in chapter 122, and uses it first in chapter 138.[25]

Type: White trion Normal Bagworm
Mikumo Bagworm
Classification: OP Optional
Border's optional trigger that renders the User invisible to Radar. He was first seen using it in chapter 140.


Osamu com

Osamu With replica

Yūma's guardian Replica sometimes helps Osamu with his duties as a Border agent, via a miniature version that has branched of the main body.

  • Communication: Replica can separate parts his body to create miniature clones which allows Osamu to communicate long range with Yūma.
  • Boost Double: Activated by Yūma using replica's main body, then a seal with the kanji For strength appears on Osamu's back. this technique reinforces Osamu's trion body and gives him a significant strength boost. Osamu was able to lift a pillar easily he previously wasn't able to budge.
  • Shield: Replica can create a shield around Osamu to block attacks.[26]


Trion Attack Defense/Support Mobility Skill Range Command Special Tactics Total
Border Briefing File[27] 2 3 4 4 5 4 6 4 32


  1. World Trigger Manga - Chapter 37, p. 7
  2. World Trigger Manga - Chapter 80, p. 11
  3. 3.0 3.1 World Trigger Manga - Chapter 12, p. 16-18
  4. World Trigger Manga - Chapter 68, p. 17
  5. World Trigger Manga - Chapter 36, p. 14
  6. World Trigger Manga - Chapter 155, p. 14
  7. World Trigger Manga - Chapter 12, p. 18-19
  8. World Trigger Manga - Chapter 69, p. 9
  9. World Trigger Manga - Chapter 69, p. 13
  10. 10.0 10.1 World Trigger Manga - Chapter 36, p. 14-15
  11. World Trigger Manga - Chapter 36, p. 15
  12. World Trigger Manga - Chapter 122, p. 17-18
  13. World Trigger Manga - Chapter 122, p. 12
  14. World Trigger Manga - Chapter 122, p. 16
  15. 15.0 15.1 World Trigger Manga - Chapter 138, p. 17
  16. World Trigger Manga - Chapter 156, p. 3
  17. World Trigger Manga - Chapter 140, p. 2-3
  18. World Trigger Manga - Chapter 141, p. 11-12
  19. World Trigger Manga - Chapter 140, p. 18
  20. World Trigger Manga - Chapter 141, p. 14
  21. World Trigger Manga - Chapter 146, p. 11-12
  22. World Trigger Manga - Chapter 143, p. 11
  23. World Trigger Manga - Chapter 156, p. 7
  24. World Trigger Manga - Chapter 145, p. 17
  25. World Trigger Manga - Chapter 138
  26. World Trigger Manga - Chapter 36, p. 12
  27. World Trigger Manga - Border Briefing File, p. 140

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