The strength of life lies in the possibility of dying.

Kouichi, episode 16

Kouichi Aizawa (相澤 虹一Aizawa Kōichi) is Rokujou's seemingly 14-year-old classmate who studies Nindō under Kumohira. Throughout the series, it is hinted that Kouichi has a romantic inclination towards Raimei Shimizu, though the girl has mentioned that Kouichi "is not her type of guy" early in the series. He is voiced by Satoshi Hino in Japanese and Chris Burnett in English.

Appearances Edit

Design   Edit

Kouichi has a tall, lean-muscled build from his training as a shinobi. He has white messy hair that matches his feathers in his animal form, and has wine-red eyes with a pair of oval-shaped glasses.

Shiratama and Kouichi

Shijima and Kouichi in their animal forms.


He is normally portrayed with an energetic attitude around other people, becoming serious and relentless when it comes to ninja duties. He has a slightly morbid fascination with death as a result of his immortality. His immortality is attributed to the holder of the Shinra Banshou during the Edo Period, who was a medical practitioner that experimented with animals, placing the wisdom of the Shinra Banshou in them.


He and Shijima Kurookano are the only survivors of the experiments and gained immortality; they believe that their mission is to observe and follow the end of Nabari.


Kouichi and Shijima

This implies that Kouichi, and subsequently Shijima, are at least a century old. Kouichi's ultimate goal is to have the Shinra Banshou release him from immortality and ensure that another immortal being or "monster" like himself is never created again. They are together referred to as the Hakutaku (白澤). The Aizawa household are descendants from Fuuma ninjas and are native Banten ninja.


He is a student in school with Miharu and he follows and protects him. One day Miharu's power the Shinra Banshou activates after being threatened and Kouichi stabs him to subdue and seal the flow of power. He continues to protect Miharu along with their sensei Tobari to protect and stop Miharu from using the Shinra Banshou.

His immortality is first found out when he is shot in the heart and bleeds to death. Later though he stops the assasins from murdering the head of the academy and during his fight Kouichi asks "Why do I always have to look like the bad guy?" After the fighting he reveals to Raimei and Tobari about his immortality.

When Miharu is kidnapped he turns himself into a owl showing why his nickname is 'bird.' He later fights with Raimei with his other friend Shijima, as they try to find out the history of the Shinra Banshou and how to use it to end their immortality. During his fight however, he finally realizes his true feelings, and tells Raimei that he loves her, the one girl in all those centuries.

Abilities & PowersEdit

Kouichi's well-versed in Kendo, Karate, Aikido and Ninjutsu. He knows how to use multiple ninja tools like: shuriken, kunai, ninja-to, tanto and more. He uses an arsenal of ninjutsus such as hypnotism and teleportation. As a result of his immortality he is able to shift into an owl since it was his original form before he had become a human.


  • Kouichi is unfazed at killing his target during missions, resulting from his years in immortality. This conflicts with Tobari's vow of not killing a single soul.
  • Character Art
  • Kouichi Sketch
  • Kouichi Full Body
  • Kouichi Full Body2
  • Koichi.jpg Kouichi
  • Friends
  • Trapping Gau
  • Kouichi and Raimei share a moment
  • Kouichi ready
  • Meetup with Gau
  • Kouchi threathened by his teacher.
  • Kouichi's eyes.
  • Kouichi protecting Miharu.
  • Nabarimain2.jpg