He is Yako's little brother. He blames Rokaku for his brother's death and seeks revenge, so he teams up with Kohei to get closer to him. However, unaware to him, Kohei is the one responsible for Yako's death. Later in the series, Kyoji finds an old feather that once belonged to Raitonaitsunaito, suggesting that Kohei has been in Rikyu in the past. Once Kyoji tells his friends this surprising news, Mahiru learns the truth that Kohei caused his big brother's death and allies himself with Reiji and the others. When Maiko asks Rokkaku why he didn't tell Mahiru the truth from the start, he said that Mahiru wouldn't have believed him anyway. Although Mahiru fought alongside with Rokkaku against Kohei, he still wasn't ready to forgive him for what happened to Yako.