Jinsuke is Keiran's older brother and the leader of the team. He’s the Red Raiju Nefilim with his elemental connection to Fire and Lava. Jinsuke is naturally adept at being a good mentor, leader, and role model to his younger brother and other family members. However, he's sometimes arrogant, doesn't set clear expectations for the people around him, and is too noble in most circumstances. Despite this, Jinsuke has a kind heart as well as sensitivity to the struggles and concerns of his family. Two years before the event of the story, Jinsuke was enrolled to study abroad in Japan. This was also when his parents disappeared there. Without hesitation, he took the opportunity to be enrolled to bring them home. He notices that Keiran has been antisocial since their parents vanished.

So, he persuaded Keiran to live with him in Japan for at least a year and a half. Much like his brother, he's determined to find his parent but also wants to seek the rest of the Raiju clan members who disappeared around the same time.