Kou has the appearance of a young man in his early 20s. In the beginning, he was a teenager dressed in a common foot soldier's clothing but he switch to the armor of a foot soldier like the rest of his unit after they become a 1000-Man unit
Kou has a caring personality, he wants to provide a good life for his mother that raised him single handedly after his father's death. His goal is to move up in status to the warrior class. He showed determination while hiding under corpses, he was stabbed but did not cry out in pain and remained silent.
Kou was born in Jouto village where he was raised by his mother. As a child, Kou grown up with the Bi brothers, Bi Hei and Bi Tou, Kei along with Shin and Hyou who were all older than Kou as he was youngest amongst them. Kou would often get dragged into trouble during Bi Hei's shenanigan or watch one of Shin and Hyou's training bouts with the rest of them.
Kou has participated in every single battle since the founding of the Hi Shin Unit.
Kou was recruited during the emergency draft after Zhao's invasion of their land, Kou went on to his first real war campaign with Kei and the Bi brothers.
When the unit became a 1000 man unit and was having a losing streak he was the first to notice that Kyou Kai leaving was a huge loss to the unit. When Shin tried to argue about her contributions he pointed out that Kyou Kai was the one who came up with all their strategies and tactics. Everyone agreed and was shocked to discover Shin and En were coming up with the tactics causing their string of defeats.
Kou approaches Kyou Rei who was vomiting away, using instinctively the erasing technique that Kyou Kai taught him. He thanked her for saving his life the day she arrived and asked her to join everyone so that she could become familiar with them. She asks him if he is afraid of her and he answers that it's the case but that they are now part of the same team.
Kyou Rei tells him not to look down on her, that he doesn't know anything, and makes him want to kill them all. He is pitifully weak and doesn't deserve to live. She plunges slowly her blade in his neck but stops when she heard the other members looking for him.
As one of the oldest veterans in the Hi Shin Army, Kou shows to be a capable soldier and is capable enough to hold his own against normal units.
Kou is capable of using a spear in battlefields. Kou was taught joint locks by Kyou Kai as well as sound muffling technique. Despite his frail looks, Kou is a physically strong soldier as he was part of the climbing team during the Battle of Eikyuu and was able to catch both Bi Hei and Rei from falling down.
- Kou was taught how to perform joint locks from Kyou Kai and has learned some forms of stealth martial arts from observing her action as even Rei was surprised by his moves.