Akachi has short black hair and red/orange colored eyes.
Akachi doesn't show emotions until he becomes angered, then he lashes out. Akachi has a chip on his shoulder from being a slave before turning into a Shinshou, his main goal is to be treated an equal by Kannagi who was his master. Akachi had a younger half-sister, Emisu, who he treasured for being his last living family member. Her death causes him to grow hatred towards Kannagi. Akachi stays calm and doesn't allow others to read him, he prefers to keep others at arms reach. He relates to Kadowaki's feelings of not wanting to be overshadowed and therefore gives his eye as a means of connecting to Kadowaki to see if he follows through with his desire. Akachi isn't a bad person deep down, but had a hard life so he doesn't allow others to mistreat him as a Shinshou. He has the respect of his Zokushou from his powerful presence.
He appear along with the other Shinshou and probably appear only in the foreshadow through the first chapter.
Akachi is first introduced when he brutally murders Kannagi's Zokushou and villagers living in his territory. Kannagi shows up and the two duel; Akachi proves victorious and claims Kannagi's Hayagami, Homura. Akachi is shown in glimpses until Hinohara and company arrive in his territory.
Kadowaki meets up with Akachi first to try making him submit. Akachi defeats Kadowaki but shows no interest in making the weak boy submit. However, after learning of Kadowaki's desire to no longer live in Hinohara's shadow he has a change of heart. Akachi gives Kadowaki one of his eyes so he can witness Kadowaki achieving his goal.
Akachi's past is shown next. Akachi and Emisu, his half-sister, were slaves purchased by Kannagi, the two had no idea about this until years later. Kannagi and Akachi develop a friendship and friendly dueling rivalry till both were in their late teens and early twenties. Kannagi's father is killed when the villagers turn mutinous. Kannagi releases Akachi and Emisu from their chains where he reveals to Akachi he was their owner not his father. Akachi remains behind to allow Kannagi and Emisu flee. When the guys are reunited they have become shinshou and Kannagi reveals Emisu's death which causes Akachi to develop hatred for Kannagi which he keeps hidden for many years.
Akachi seperates Arata's company; he manages to find Kannagi and the two begin dueling. The fight becomes a "fight to the death." Kannagi manages to launch the final blow defeating Akachi. The two reconcile and Akachi reveals his only wish was to become Kannagi's equal. He then reveals the time he stayed behind to allow Kannagi and Emisu escape, he was murdered and is now a wandering corpse. Akachi submits to Kannagi, and dies peacefully where is reunited with Emisu who tells him they were finally able to meet each other without shackles separating them. Akachi gives her a peaceful smile before they fade away.
Okoro (地龍, Okoro)
- Kadowaki: Acts as a mentor towards the boy since he sees similarities between the two of them.
- Emisu: Akachi's half-sister that he treasured. The two were very close and Akachi made certain no harm befell the girl. Emisu may had feelings for Akachi, who she didn't know was her sibling. Emisu was Akachi's light with the warmth she radiated. Her death affects him deeply.
- Kannagi: Akachi's master in the past and best friend. The two grew close growing up as children along with Emisu. Akachi is uncertain how to respond to Kannagi's blunt behavior and is unsure why Kannagi wishes to befriend him. Akachi teaches Kannagi how to fight in friendly sparring matches. As adults, Akachi becomes bitter from being a slave and is shocked upon learning Kannagi is the one who bought him and Emisu. When villagers slaughter Kannagi's father in a rebellion, Kannagi releases them and the three escape, except Akachi stays behind to give the two an opportunity to make a getaway. Later on, both men become shinshou and upon learning of Emisu's death Akachi begins to hate Kannagi. (He slaughters villagers in Kannagi's as a form of betrayal). In the end, he reveals he wished to be accepted as Kannagi's equal.