All that matters is this. I DO have a part to play in this world. I'm the brilliant detective, and I'm here to solve the mystery of Kaeru's death.

Sakaido, FILE: 01 Jigsawed

Brilliant Detective Sakaido is the persona adopted by Akihito Narihisago whenever he enters id wells and the main protagonist of ID:INVADED. The original and most prolific "brilliant detective", he traverses the id wells of serial killers to try to uncover the truth behind the murder of Kaeru, and indirectly determine the identity of the id well's owner for Kura.[4][5]


Sakaido's appearance is extremely reminiscent of his counterpart Akihito, essentially being a younger version of him, appearing as a young man with green eyes and light pink hair spiked upwards. His clothing consists of a long brown trench coat, a lighter shirt, and a black vest[6], as well as large, flared black shorts, black leggings, and trainers. Most noticeably, he has a long yellow scarf.

While in Tamostu Fukuda's id well, his left arm is disassembled, losing his wrist, part of his forearm and his elbow.


The quirks of the Mizuhanome System mean that Sakaido remembers nothing of his life as Akihito every time he enters a new Id Well, essentially leaving him a blank slate each time he wakes up, meaning his personality is more innocent than Narihisago's, lacking the latter's trauma.

Though not immune to panic, Sakaido does show a calm, proactive mindset, quick to calm down and take proper action, shown when he discovered he could move his detached limbs and calmly put himself back together. He also was unfazed by seeing a young girl's corpse and the broken, distorted people of Fukuda's well, showing that he possesses impressive nerves.

Sakaido is also characterised by his extreme deductive mindset, being highly analytical and methodical in his work, perfectly willing to spend time focused on one particular clue, only moving on once satisfied, prioritising the case over his own survival. However, despite this drive, Sakaido is extremely empathetic, often taking into account the people in the case as people rather than just clues, occasionally derailing his investigation entirely to save someone in immediate danger. While in Nahosi Inami's id well, he cries over Kaeru's body, realising her death had no point and despairing that he couldn't save her.



  • The surname Sakaido means "liquor, sake, alcohol, booze" (酒) (saka), "well, mine shaft, pit" (井) (i) and "door" (戸) (to/do).
    • Like the other brilliant detectives, Sakaido's name is a reference to the id wells, containing both the kanji for "well" (井) and "id" when spelt in the Latin alphabet.
      • Sakaido's name is a reference the naming convention used for most characters in ID: INVADED, who are named after various brands of alcohol.



Characters in ID:INVADED
Protagonists Akihito Narihisago / SakaidoKoharu Hondomachi / Miyo HijiriidoTamotsu Fukuda / AnaidoFunetaro MomokiKokuryu Matsuoka
Supporting Characters Sarina TogoShirou KokufuSennosuke ShiratakeKazuo WakashikaMasamune HabutaeTakuhiko HayaseuraKiki Asukai / KaeruTsukimaru NishimuraAyako NarihisagoMuku Narihisago
Antagonists Koji FuyukawaGenpei OonoHaruka KazutaNahoshi InamiDenshin KatsuyamaJohn Walker / Uraido
Minor Characters Keiko KikuchiNishio ShirakomaHitoshi SonodaFukusen
Characters in #BRAKE-BROKEN
Protagonists Akihito Narihisago / SakaidoKoharu Hondomachi / Miyo HijiriidoFukusen
Supporting Characters Funetaro MomokiKokuryu MatsuokaFukusenSarina TogoShirou KokufuSennosuke ShiratakeKazuo WakashikaMasamune HabutaeNahoshi Inami / HakaidoKitanoHatakeyamaKaeru
Antagonists Mana Tsurumi
Minor Characters Anaido
Characters in ID:REMEMBERED
Narrator Akihito Narihisago / Sakaido
Characters Ayako NarihisagoMuku NarihisagoThird DaughterHitoshi Sonoda
Characters in ID:INDEED
Characters Akihito Narihisago / SakaidoKoharu Hondomachi / Miyo HijiriidoTamotsu Fukuda / AnaidoFunetaro MomokiKokuryu MatsuokaSarina TogoShirou KokufuSennosuke ShiratakeKazuo WakashikaMasamune HabutaeTakuhiko HayaseuraNahoshi InamiHaruka KazutaEi Aoki