One of the strongest and oldest members of the Raiju Clan. Akitoshi is the Grey Raiju Nefilims, with the strongest connection to the Divine spirits. He's self-assured, steadfast, and care-taking towards his family but ruthless and heartless towards his enemies. A few years before the event of the story, Akitoshi caught wind of a teenage boy with black bloodshot eyes, slaughtering and kidnapping a few members of the Raiju Clan from different regions in Japan. He contacted all remaining members to be aware of this individual as he has a connection to an extinct clan that where erased from history since the Sengoku Period. Unfortunately, his family became the victims of these serial hunts and had no choice but to infiltrate and stop him. He was aided by a few remaining members (including the Mark brothers' Father who trying to rescue their mother), however, the boy overpowered the team, killing two of the members and kidnapping the father, leading Akitoshi to retreat from the fight. Two years later, the guilt of not protecting his family and his clan members took a mental toll on him. He was hell-bent on trying to be stronger and find this demonic individual but with no success. He later came across the Mark brothers, Isshin and Junko while visiting the site where Akitoshi's family was murdered and he quickly realized who they were. While getting to know one another, Jayson thinks that with the newfound power passed down for generations, he suggests that this team should carry the mantle and retrieve what they have lost. At first, Akitoshi was against it as he didn't want to lose any more family members. But eventually, saw potential in them, and decided to teach them everything he knew.