Next, the most popular, all-purpose blade: Kogetsu, "Arc Moon".

–Shiori Usami, in Arashiyama Unit 2.[1]

Kogetsu [1]

Kogetsu anime


Kanji 弧月
Rōmaji Kogetsu
Organization BrDr Border
Type White trion Normal
Classification Kogetsu icon Attacker
- High attack power
- Durable blade
First Appearance
Manga Chapter 14
Anime Episode 7

Offensive Power A
Durability A
Lightness C
Type Balance

Kogetsu (弧月(こげつ)? lit. Arc Moon) is an Attacker Trigger.


Kogetsu's appearance is akin to that of a katana, with a luminous yellow blade made of trion, but without a tsuba (guard). A black-blade Kogetsu was also used by Kō Murakami in Round 7 of the B-rank battles.


Until a few years before the start of the series, Kogetsu was the sole Attacker Trigger in existence.[2] Its origin seems to date back at least to the days of Old Border.[3]


Mirroring its popularity, Kogetsu is considered the best-made Attacker Trigger out of the three, as well as the most balanced. It boasts high offensive power, and it is more durable than Scorpion,[1] making it possible to intercept the attacks of other blade Triggers a great many times without the blade risking to break.[4] It is the Trigger of choice of aggressive Attackers and All-Rounders.[5] A single swing of Kogetsu can crack a focused Shield and break it if pressure continues to be applied,[6] although this is not the case against the focused barriers generated by Idras.[7] Unlike Scorpion and Raygust, Kogetsu cannot shapeshift; however, its blade can be temporarily extended by combining it with the Optional Trigger Senkū,[8] or its shape manipulated with Gen'yō,[9] another Optional Trigger.

Much like Gun Triggers[10] and Raygust's handle,[11] Kogetsu can be turned off in order to use other Triggers without the need to dispel it, and even without putting it back in its scabbard.[12] As long as it remains off, the blade will not be able to cut anything.[10] However, since, unlike Scorpion, it cannot be manifested or withdrawn at will,[1] a blunt Kogetsu can prove to be a burden.[10] To avoid this inconvenience, it is possible to dispel both the blade and the scabbard[13] and conjure them again when needed[14] at the expense of some trion.[10] A new Kogetsu blade can be materialized even without destroying the scabbard, which can prove useful should the user be disarmed[15] or the blade become unfit for use.[16] While inside its scabbard, Kogetsu can be broken with just one Senkū slash.[17]

One of the few downsides to Kogetsu is its weight.[1] If it is not wielded with both hands, the user may be thrown off-balance,[18] or underperform as a result of their swordplay getting slower.[19] However, agents who have reached Master Class routinely show to be capable of holding it with only one hand without difficulty.[20][21][22] A very circumstantial drawback of Kogetsu is that, like the other Attacker Triggers, or at least Raygust,[23] it has a luminescent blade; however, its color can be changed to black with the help of an engineer, eliminating the glow and thus rendering Kogetsu invisible in the darkness.[24]


See also: Kogetsu Users

Many Old Border agents used this Trigger.[3] Currently, there are 28 known official agents (B-rank and above) with at least one Kogetsu in their Trigger set,[25] including Hyuse;[26] if Yōsuke Yoneya's modified Kogetsu is included in the list, the number goes up to 29. Among HQ personnel, Masafumi Shinoda, believed to be HQ's strongest Trigger user and Kei Tachikawa's swordsmanship teacher,[27] deserves to be mentioned as well. A recurring user who is not an official agent is Hidehide Hinoe.[28] The list excludes those members of branches who do not participate in rank battles.[29]

The Kogetsu user with the most Solo Usage Points is Kei Tachikawa, the no. 1 Attacker and solo combatant. Yūichi Jin, Raizō Terashima and Kirie Konami[30] are notable among the former users of this Trigger.


  • According to the author, sometimes, when a Kogetsu suddenly disappears, it is because he has forgotten to draw it.[31]
  • The concept of a black Kogetsu was teased by the author in the official databook[32] prior to its appearance in the series.


  1. 1.0 1.1 1.2 1.3 1.4 World Trigger Manga Chapter 26 (p. 5)
  2. World Trigger Manga Chapter 27 (p. 9)
  3. 3.0 3.1 World Trigger Manga Chapter 1 (p. 7)
  4. World Trigger Manga Chapter 97 (p. 3)
  5. World Trigger Manga Chapter 26 (p. 27)
  6. World Trigger Manga Chapter 99 (p. 6)
  7. World Trigger Manga Chapter 129 (p. 10)
  8. World Trigger Manga Chapter 26 (p. 5-6)
  9. World Trigger MangaBorder Briefing File (p. 154)
  10. 10.0 10.1 10.2 10.3 Daisuke Ashihara: Even without putting it in a sheath you can turn the Kogetsu OFF, but the sharpness will become zero. You won’t be able to use it and you can’t deactivate it either so it’s a big hindrance. Deactivating the Kogetsu and then remaking one later when you need it again will mean it’s not a hindrance, but it will use up trion. It is the same as gun type triggers.
    Source: Question Corner 9, Volume 10
  11. World Trigger Manga Chapter 152 (p. 13)
  12. World Trigger Manga Chapter 153 (p. 7)
  13. Daisuke Ashihara: ‘Putting away Scorpion’ is similar to ‘putting Kogetsu back in its scabbard’. They’re both out of the way, but Scorpion is less of a burden. ‘Turning off Kogetsu’ means to destroy both the scabbard with the blade.
    Source: Question Corner 10, Volume 13
  14. World Trigger Manga Chapter 141 (p. 4)
  15. World Trigger Manga Chapter 114 (p. 17-18)
  16. World Trigger Manga Chapter 157 (p. 13)
  17. World Trigger Manga Chapter 157 (p. 10)
  18. World Trigger Manga Chapter 139 (p. 7)
  19. World Trigger Manga Chapter 99 (p. 7)
  20. World Trigger Manga Chapter 15 (p. 3)
  21. World Trigger Manga Chapter 113 (p. 12)
  22. World Trigger Manga Chapter 157 (p. 1)
  23. World Trigger Manga Chapter 168 (p. 21)
  24. World Trigger Manga Chapter 169 (p. 9)
  25. World Trigger MangaBorder Briefing File
  26. World Trigger Manga Chapter 161 (p. 14)
  27. World Trigger MangaBorder Briefing File (p. 28)
  28. World Trigger Manga Chapter 38 (p. 8)
  29. World Trigger Manga Volume 18
  30. World Trigger Manga Chapter 1 (p. 14)
  31. Daisuke Ashihara: Once the Kogetsu is selected, it is always out. It disappears in the art sometimes, but that's just me forgetting to draw it.
    Source: Question Corner 5, Volume 7
  32. World Trigger MangaBorder Briefing File


e - d - vBorder Triggers
Basic Equipment Bail OutRadarTrion Body
Attacker Kogetsu (Kogetsu: Spear) • Raygust (Shield Mode) • ScorpionSōgetsu (Axe)
Gunner Asteroid • Cobra • Gimlet • Hornet • HoundMeteorSalamanderTomahawkViper
Firearms Assault Rifle • Grenade Launcher • Handgun • Minigun • Shotgun
Sniper EagletIbisLightning
Defense EscudoShield (Affixed Mode/Full Guard)
Trap Switchbox
Optional Bagworm • Bagworm Tag • ChameleonConnector • Dummy Beacon • Enhanced Radar • Full ArmsGeistGen'yōGrasshopperIdatenLead Bullet • Makō • Senkū • Silencer • SpiderStarmakerTeleporterThruster • Timer
Prototypes Connector • Dummy Beacon • Full ArmsGeistIdaten • Makō • Teleporter • Timer
Black Fūjin • Tsukihiko Amō's Black Trigger • Yūma Kuga's Black Trigger

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