Kouichi Aizawa

"As shinobi, we must always put our lives on the line in battle. If you're going to seek mercy from your enemy, you have no business in Nabari."

- Kouichi Aizawa Kouichi Aizawa is one of the main protagonists of the manga/anime series Nabari no Ou. He is a student and classmate of Miharu Rokujo who studies ninja techniques under Tobari Durandal Kumohira. It is later revealed that he is actually an immortal owl in human form. 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 is voiced by Satoshi Hino in the Japanese version of the anime and Chris Burnett in the English version, the former of whom also voices Yuji Sakai and Shiage Hamazura.

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

Personality
Kouichi in generally an energetic and friendly person who is normally seen smiling. He is very tolerant of Miharu's apathetic attitude (as opposed to Tobari, who is often annoyed by it) and quickly gets along with Raimei very soon after meeting her. He is 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 extremely pragmatic and ruthless, 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 Miharu. Because of this ruthless nature, Kouichi is usually the one to call out Tobari for his inability to take a life, going so far as to call him a coward.

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. Due to living for centuries, Kouichi has grown to view his immortality as a curse and wishes to be free from it, eventually desiring for Miharu to use the Shinra Banshou to grant his wish.