Eiji Ryuugasaki

Eiji was the father Hiro Ryuugasaki and close friends of Leon Aurenche. Along his wife Asagi Ryūgasaki, they worked along Leon in Genesis Corporation, researching the Tree of Woe, which eventually lead to Asagi being possessed by Nexus. During the evacuation following the Tree of Woe spiraling out of control, Eiji sacrificed himself to ensure the containment of the Tree of Woe and entrusted Leon to take care of stopping its eventual revival, not knowing that it was Leon who actually planned all it to happen. Since that incident, Asagi and Eiji's son had been living with his paternal grandfather.

Eiji ended up trapped in an alien world, where he lost all hope while searching for his wife. In his last moments, Nexus appeared in front of him in Asagi's body, telling him that he could win back Asagi by helping to bring eternal sleep to his world. Thus, Eiji has aligned himself with the Tree of Woe in hopes of saving his wife.

After sending the Empty Shadows through the Tree of Woe, Eiji appears after the battle between Hiro, Luca Yonazuki, and Mauro Abelard. After revealing himself as the one responsible for the destruction of the world, Hiro decides to face him in battle. Although Hiro manages to win thanks to the Prominence Fusion that Mauro gave him, the Tree of Woe ends up opening and absorbing everyone.

When Hiro and his friends return to reality, he climbs the tower to face his father again and stop Nexus. Although Hiro seems to have lost, he manages to win thanks to Rowen giving his Mythical Card a new power. Eiji then decides to place his trust in his son, giving him the key to get to where Nexus is and also entrusting him with a special data that he couldn't master, which ends up giving Ignis Dragon the ability to evolve into Ignis Dragon Nova.

When the Tree of Woe tower disappears, Leon falls into the void and awakens to be greeted by Eiji and Asagi. The three then set off for an unknown destination. Eiji is later seen watching Hiro and Luca's battle at the finals of the second National Tournament.

Three years later, during Shadowverse Flame, Eiji and Asagi reappears in middle of the Arc Ruler's invasion of Nekome City to save Hiro and Luca from the Shades. Eiji uses Shadow Ignis Dragon to fight along them.

Following the defeat of Wolfram Zerga and the disappearance of the Tree of Woe, Eiji and Asagi leave for America with Leon to continue their research to change the world.

Eiji used to be a kind man, as well as a good husband and father. However, following isolation in the Tree of Woe and the influence of Nexus's power, Eiji became cold and ruthless, willing to destroy the world in order to save his wife. After losing to Hiro for the second time, Eiji regained some of his old feelings. After disappearing along Leon and Asagi, Eiji seems to have returned to his former self.