World Trigger Wiki
World Trigger Wiki
Slinking off to lick our wounds doesn't sit well with me. If we gotta bail out, I wanna do it in a blaze of glory... Well, that's what I'd normally say...

Noboru Koarai to his teammates, in Azuma Unit 2.[1]

Noboru Koarai (()(あら)() (のぼる) Koarai Noboru?) is a B-rank Attacker and a member of the latest generation of Azuma Unit.


Koarai is a light-skinned boy of average build. He has slit pupils and short-to-medium dark blonde hair that is slicked into an upturned point in the front. He seems to favor wearing light, dark-colored jackets,[8][9] although he has also been seen donning hoodies.[10]

In his trion body he wears a navy blue, long-sleeved jacket with black lines bordering the zipper and the high collar, which he keeps open, and running horizontally around it both on the inside and the outside. Vertical black stripes run from the collar to the wrists of the jacket, interrupted only where Border's logo is emblazoned on the outer side of each sleeve a little below the wearer's shoulders. On the right breast are two piped patch pockets closed by flaps, bigger than the ones that can be found in the vicinity of his left hip, while on the left is the B-rank logo. Underneath the jacket is a black shirt with a round neck. The uniform is completed by dark gray boots and headphones and a pair of black pants.


Koarai is high-spirited[11][12] and easily excitable,[13][14] and wears his heart on his sleeve.[15][10][11] He has a competitive side, which is most visible when he discusses strategy with Okudera in front of their captain[16][8] and when he fights in rank battles[17] as well as when he cheers for others.[18][19][20] Nonetheless, he shows no hints of resentment when he loses, instead congratulating the winner with enthusiasm[21] and admiring more skilled Attackers.[20] He can be defensive about his own abilities, although he is willing to recognize his shortcomings for the good of the team.[22] He can act a little smug when things go his way.[8][23][24]

Koarai has a well-deserved reputation for being reckless in combat,[3] attacking a Rabbit on his own after it pounced on Okudera against his captain's advice[15] and preferring to fight to the last even when retreating is the best move. However, he was recently noted to have grown more prudent,[1][3] even though agreeing to retreat left him feeling dejected.[9] In the planning phase of rank battles he has occasionally exhibited a penchant for suggesting courses of action based purely on how entertaining they had the potential to be.[8] It is possible that this tendency of his has also subsided, as in round eight Azuma Unit chose Exhibition Hall, a map where Azuma is known to excel.[4]


Tsuneyuki Okudera[]

Koarai and Okudera are teammates who seem to enjoy a good relationship[25] and a friendly rivalry when discussing strategy in the presence of Azuma.[16][8] Due to their differing personalities, Okudera may end up in some of Koarai's more reckless tendencies,[22][26] and may feel frustrated when Koarai acts smug around him.[8][24] This however does not diminish the concern Koarai shows for Okudera in combat,[15][27] and the latter has also demonstrated to care about Koarai's mood.[9] They address each other by surname, without honorifics.[15][28]

Haruaki Azuma[]

Azuma is Koarai's captain and mentor.[29][12] He educates him in strategy while giving him the space to come up with his own plans.[30] In addition, he is to an extent responsible for Koarai's Trigger Set, having forbidden him to equip Sub Triggers until he showed to have grown enough.[9] Koarai greatly respects Azuma and is filled with pride when validated by him.[8][24] His admiration dates to before he joined Azuma Unit, as he clung to the captain's leg and begged for the chance to be part of it.[31] They address each other by surname,[32] with Koarai adding the honorific -san.[8]

Mako Hitomi[]

Hitomi is a big sister figure to Koarai and Okudera, who joined Border when she did,[31] and she may invite them to cool down when their discussions turn into ego battles.[16] He has grown accustomed to finding her giggling while watching horror movies in the dark in the strategy room.[33] Koarai calls her by name, to which he appends the honorific -san,[34] while she uses his nickname without honorifics.[10]

Taichi Betsuyaku[]

Betsuyaku is school friends with Koarai,[31] whom he refers to by the nickname "Koala", without honorifics,[2] seemingly connoting a rather close relationship.

Ken Satori[]

Koarai and Satori are school friends.[31]

Hisato Sasamori[]

Koarai and Sasamori are of an age and might be close, seeing as they were seen walking together in the base.[35] Koarai was enthusiastic about Sasamori's one victory against Hyuse.[18]

Tatsuhito Ikoma[]

Koarai and Ikoma are presumably on good terms, with Koarai feeling entitled to bemoan Ikoma's involuntary foul when he sparred with Hyuse.[36] Koarai addresses Ikoma by shortening his surname and appending the honorific -san, while Ikoma uses Koarai's nickname and no honorifics.[37]

Kō Murakami[]

Koarai and Murakami might be close, since the former referred to the latter by his first name, albeit with the addition of the honorific -san.[36]

Shinnosuke Tsuji[]

Koarai is presumably somewhat close with Tsuji, taunting him when they clashed in round four.[23] For his part, Tsuji appears not to mind Koarai's informality.[38] Nonetheless, Koarai acknowledges Tsuji's superior swordsmanship[13] and addresses him respectfully, using his surname and the honorific -senpai.[23][38]

Sumiharu Inukai[]

Inukai knows Koarai well enough to be able to tell that he would generally prefer to hope in a final shot rather than retreat, as well as to call him by his nickname without adding an honorific.[3]

Nozomi Kako[]

Kako knows Koarai well enough to be able to accurately guess that it was his idea to give the map for round four a snow setting. She refers to him by his surname followed by the suffix -kun.[39]

Jun Arashiyama[]

Arashiyama knows Koarai well enough to be able to tell that he would generally prefer to hope in a final shot rather than retreat.[3]

Yūta Miura[]

Koarai and Miura are familiar with each other at least by sight,[40] although Miura's popularity among younger Attackers[41] could imply that they are closer than that. Koarai addresses him by his surname followed by the honorific -senpai,[40] suggesting respect.


Koarai was deeply impressed with Hyuse's combat prowess. Though losing all five rounds to him[42] and subsequently rooting for his opponents,[18][19][20] he later enthusiastically greeted and complimented the recruit,[21] going so far as to invite him to join Azuma Unit.[11]


  • (Azuma's motto, taken up by Koarai and Okudera) "When you fight with strategy, take into account the enemy's strategic prowess."[43]
  • (To Haruaki Azuma) "I really think we should tweak the map. It would be super fun."[8]
  • (To Tsuneyuki Okudera) "I'm sure we'll get more ideas if it's more fun."[8]
  • (To his teammates) "Slinking off to lick our wounds doesn't sit well with me. If we gotta bail out, I wanna do it in a blaze of glory... Well, that's what I'd normally say..."[1]
  • "They think I've grown? That's nice and all. But all I could actually do in the end was run away..."[9]


  • "Noboru ((のぼる)?) means "rise, mount, board, climb", while "Koarai" (小荒井(こあらい)?) means "small wasteland pit".
  • He likes soccer and karaage fried chicken.[12]
  • Despite Koarai and Okudera using Grasshopper in both rank battles in which they appeared,[44][5] as well as it being included in their Trigger Sets in Border Briefing File,[45] it is in fact a Trigger which they add only before certain matches.[46][5]


  1. 1.0 1.1 1.2 World Trigger Manga Chapter 174 (p. 5)
  2. 2.0 2.1 World Trigger Manga Chapter 167 (p. 10)
  3. 3.0 3.1 3.2 3.3 3.4 World Trigger Manga Chapter 175 (p. 17)
  4. 4.0 4.1 World Trigger Manga Chapter 184 (p. 2)
  5. 5.0 5.1 5.2 World Trigger Manga Chapter 166 (p. 9)
  6. World Trigger Manga Chapter 112 (p. 15)
  7. World Trigger Manga Chapter 159 (p. 9)
  8. 8.0 8.1 8.2 8.3 8.4 8.5 8.6 8.7 8.8 8.9 World Trigger Manga Chapter 111 (p. 1)
  9. 9.0 9.1 9.2 9.3 9.4 World Trigger Manga Chapter 175 (p. 18)
  10. 10.0 10.1 10.2 World Trigger Manga Chapter 45 (p. 11)
  11. 11.0 11.1 11.2 World Trigger Manga Chapter 160 (p. 11)
  12. 12.0 12.1 12.2 World Trigger MangaBorder Briefing File (p. 134)
  13. 13.0 13.1 World Trigger Manga Chapter 159 (p. 18)
  14. World Trigger Manga Chapter 165 (p. 8)
  15. 15.0 15.1 15.2 15.3 World Trigger Manga Chapter 45 (p. 6)
  16. 16.0 16.1 16.2 World Trigger Manga Chapter 110 (p. 9)
  17. World Trigger Manga Chapter 159 (p. 13)
  18. 18.0 18.1 18.2 World Trigger Manga Chapter 159 (p. 16)
  19. 19.0 19.1 World Trigger Manga Chapter 160 (p. 3)
  20. 20.0 20.1 20.2 World Trigger Manga Chapter 160 (p. 8)
  21. 21.0 21.1 World Trigger Manga Chapter 160 (p. 10)
  22. 22.0 22.1 World Trigger Manga Chapter 166 (p. 11)
  23. 23.0 23.1 23.2 World Trigger Manga Chapter 112 (p. 14)
  24. 24.0 24.1 24.2 World Trigger Manga Chapter 115 (p. 4)
  25. World Trigger Manga Chapter 166 (p. 12)
  26. World Trigger MangaBorder Briefing File (p. 135)
  27. World Trigger Manga Chapter 114 (p. 16)
  28. World Trigger Manga Chapter 114 (p. 9)
  29. World Trigger MangaBorder Briefing File (p. 130)
  30. World Trigger MangaBorder Briefing File (p. 133)
  31. 31.0 31.1 31.2 31.3 Volume 14 Character Profiles
  32. World Trigger Manga Chapter 45 (p. 9)
  33. Azuma Unit Strategy Room, Volume 13
  34. World Trigger Manga Chapter 174 (p. 6)
  35. World Trigger Manga Chapter 159 (p. 11)
  36. 36.0 36.1 World Trigger Manga Chapter 160 (p. 7)
  37. World Trigger Manga Chapter 159 (p. 19)
  38. 38.0 38.1 World Trigger Manga Chapter 159 (p. 17)
  39. World Trigger Manga Chapter 111 (p. 2)
  40. 40.0 40.1 World Trigger Manga Chapter 159 (p. 12)
  41. Volume 17 character profile
  42. World Trigger Manga Chapter 159 (p. 14)
  43. World Trigger Manga Chapter 110 (p. 12)
  44. World Trigger Manga Chapter 114 (p. 3)
  45. World Trigger MangaBorder Briefing File (p. 134-135)
  46. World Trigger Manga Chapter 111 (p. 4)


Trigger: Ibis  •  Egret  •  Lightning  •  Kogetsu  •  Senkū  •  Dummy Beacon  •  Grasshopper  •  Shield  •  Bagworm
Side Effect:
e d vBorder
Commander in Chief Masamune Kido
Administration Eizō NetsukiKatsumi KarasawaKyōko SawamuraMasafumi ShinodaMotokichi KinutaTakumi Rindō
General Staff Mikhael CroninRaizō TerashimaSeiji Mizunuma
S-Rank Tsukihiko Amō
A-Rank Ai KitoraAsumi AmakuraFutaba KuroeHayato UnoIsami TōmaJun ArashiyamaKazuma SatomiKei TachikawaKen SatoriKirie KonamiKōhei IzumiKyōsuke KarasumaMai KitagawaMitsuru TokiedaNozomi KakoReiji KizakiRyō UtagawaRyūji SaekiShinji FuyushimaShirō KikuchiharaShōhei KoderaShūji MiwaShun MidorikawaSōya KazamaTakaaki KatagiriTakeru YuigaTōichirō MomozonoTōru NarasakaYōsuke YoneyaYūichi JinYukimaru Ichijō
B-Rank Atsushi HokariChika AmatoriDaichi TsutsumiFumika TeruyaHanao TsukimiHaruaki AzumaHidetaka KitazoeHiro KitazoeHisato Sasamori • Hitoshi Matsushiro • HyuseItsuki FujisawaKai MinamisawaKazuaki ŌjiKazuki KurauchiKazuto TonookaKeizō MamiyaKō MurakamiKōji OkiKōtarō SuwaKotarō TomoeKuniharu KakizakiMakoto Chano • Mamoru Tokiwa • Masakuni Hakoda • Masataka NinomiyaMasato KageuraMinoru HataMitsuya KoinumaNoboru KoaraiOsamu MikumoRei NasuRokurō Wakamura • Ryōgo Funabashi • Satoru Hayakawa • Satoshi Mizukami • Seiji Marui • Shinnosuke Tsuji • Shō Motegi • Sumiharu InukaiTaichi Betsuyaku • Takahiro Ebina • Takuma YubaTatsuhito IkomaTatsuya KurumaTetsuji Arafune • Tokiya Saitō • Tsuneyuki Okudera • Waka Utsunomiya • Wataru UrushimaYōko Katori • Yoshinobu Kera • Yoshito HanzakiYūichirō YoshizatoYukari Obishima • Yukito Otokawa • Yūko KumagaiYūma KugaYūta MiuraYutaka Kashio • Yūya Tsuchisaki • Yuzuru Ema
C-Rank Fumifumi SaotomeHidehide HinoeIzuho NatsumeTeruteru Kōda
Operators Aki HiyamiAn KobayakawaAoi Kusumoto • Asami Taya • Asuka Asagiri • Ayumu Hatori • Hana SomeiHaruka AyatsujiHaya Kittaka • Hazuki Nanao • Hikari NireKaho MikamiKarin YuitsukaMadoka UiMako HitomiMaori HosoiMegumi TokuraNono FujimaruRen TsukimiRika RokutaRin KagamiRisa MakiRui OsanoSaki KusakabeSakurako TaketomiSayoko ShikiShiori UsamiYuka KonYuri RindōYuu Kunichika
Former Border Agents Akane HiuraMirai HatoharaShin KazamaSōichi MogamiTadaomi KandaYūgo Kuga
Affiliated Personel RaijinmaruReplicaRinji AmatoriRuka ShinodaYōtarō Rindō
Squads Arafune SquadArashiyama SquadAzuma SquadChano SquadEbina SquadFuyushima SquadHayakawa SquadIkoma SquadKageura SquadKakizaki SquadKako SquadKatagiri SquadKatori SquadKazama SquadKizaki SquadKuruma SquadKusakabe SquadKōda SquadMamiya SquadMatsushiro SquadMikumo SquadMiwa SquadNasu SquadNinomiya SquadŌji SquadSuwa SquadTachikawa SquadTokiwa SquadUrushima SquadYoshizato SquadYuba Squad
Branches Hayanuma Branch • Hisama Branch • Suzunari BranchTamakoma Branch • Wataayu Branch • Yumite District Branch
Factions Kido FactionShinoda FactionTamakoma Branch
Triggers AsteroidBagworm • Bagworm Tag • Bail OutChameleon • Cobra • ConnectorDummy BeaconEgret • Enhanced Radar • EscudoFūjinFull ArmsFull AttackGeistGimletGrasshopperHornetHoundIbisIdatenKogetsu (Spear/Gen'yō/Senkū) • Lead BulletLightning • Makō • MeteorRadarRaygust (Shield Mode/Thruster) • RingSalamanderScorpionShield (Fixed Mode/Full Guard) • Silencer • Sōgetsu (Axe) • SpiderStarmakerSwitchboxTeleporter • Timer • TomahawkTrion BodyViper