Kanji is Jun's schoolmate and friend.
Before his fight begins, he reveals to Jun that despite seeing him hurting Kana, he did not intervene because his sister asked him not to. He also shares a secret with Jun that alters his perspective about her, and asks him to look after Machi. Kanji's opponent is one of the most peculiar in the manga as it initially soars into the sky, lands in Hawaii, and then starts firing powerful shots at a cannon orbiting Earth, redirecting them towards Zearth. After Japan's attempt to defeat the enemy with a nuclear bomb fails, Jun suggests Kanji use lasers to target the enemy. Although Kanji couldn't directly target the enemy, a human soul could serve as a target, and Seki volunteers immediately. Koemushi teleports Seki and 22 soldiers near the enemy, and Seki bravely reaches the enemy just in time for Kanji to fire, defeating it. His chair was a folding chair that often spun and flipped when he sat in it. After the victory, Kanji requests Koemushi to teleport him to the top of Chutenro tower where he ponders who the next pilot will be in his final moments.
Kanji's role is more detailed in the anime series. He is the son of Yoshikawa Mitsue, a lead researcher tasked with unlocking the secrets behind Zearth's technology. Additionally, he becomes emotionally involved with Anko when her family faces a scandal. With his support, Anko gains strength to handle her situation and defeat her enemy. As she passes out, Kanji holds her body and has a vision of mysterious figures whom he believes are behind the battles they must fight. At one point, Koemushi tells Machi that he chose Kanji for the final battle, but after serious discussions with him, especially after discovering Koemushi's true nature, he changes his mind, having Kanji battle earlier.
