Nabari No Ou Wiki

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.


Design   []

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.

Shijima and Kouichi in their animal forms.


On the surface, Kouichi appears to be a very energetic and friendly person. He is normally seen smiling and gets along with just about anyone he meets. He is also very tolerant of Miharu's apathetic attitude (as opposed to Tobari, who is often annoyed by it), though this tolerance does have its limits. He is also quite a persistent person, repeatedly attempting to get Miharu to join his and Kumohira's ninjitsu club despite his clear lack of interest.

However, Kouichi also has a dark side; during confrontations with other shinobi, he is highly pragmatic and merciless, never hesitating to kill and even stating that in Nabari, it's kill or be killed. This side of him is noted by Raimei, who never guessed that such a nice person could be so ruthless. When fighting, he maintains an eerily calm demeanour, and often smiles after killing someone. A notable example of this is when he shoots Mr. Frosty dead with a gun and then smiles like nothing happened, an action that shocks even the apathetic Miharu. Because of this ruthless nature, Kouichi is usually the one to call out Tobari for his inability to take a life, especially since it makes his mission of protecting Miharu difficult. As far as Kouichi is concerned, a person who can't protect the people close to them is no different from a murderer.

Having been around since the Edo period, Kouichi is highly intelligent, displaying extensive knowledge of various ninjitsu techniques as well as the world of Nabari. He has a slightly morbid fascination with death, due to the fact that he couldn't die even if he wanted to. Having lived for centuries, Kouichi has grown to view his immortality as a curse and wishes to be free from it, saying that he's tired of everyone he knows and loves dying around him while he lives on, since he hates being alone, showing that he truly cherishes his friends in spite of his ruthless nature. Because of his immortality, Kouichi also tends to react to dangerous and even deadly situations calmly.

In contrast to Tobari, who is determined to keep Miharu from ever using the Shinra Banshou, Kouichi is rather conflicted about whether or not he wants Miharu to use it; on one hand, he wants to be mortal again, and sees the Shinra Banshou as the perfect way to become such. However, the Shinra Banshou is also the reason he became immortal in the first place, so he can also sympathise with Tobari's desire to have it sealed away forever, so it'll never bother anyone again. Overtime in the manga, however, he decides to help Miharu become strong enough to use the Shinra Banshou, having decided that there's no other way for him to lose his immortality. In the anime, however, this doesn't happen and he is content with living out his life as "Kouichi Aizawa".


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 & Powers[]

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.