In an act of desperation, Hibiki attempts to use the saber, only to meet the same result as Todoroki. The two Oni then lose the ability to transform. In the past when this has happened, Oni were unable to ever regain their powers, but as Danki and Shouki revealed, when Kogure used them as his guinea pigs, if an Oni is put through intense training, their powers will eventually return. Through his training with Kogure, Hibiki, along with Todoroki, regain their powers. In the next battle after regaining their powers, Hibiki and Todoroki are pit against one of the strongest known Makamou. Kogure appears and throws Hibiki the Armed Saber, telling him that it was always destined to be used by him and that it will unlock his true power. A hesitant Hibiki finally uses the saber and easily defeats the Makamou. Hibiki meets another boy named named Kyosuke, who was estranged from his father and when he met Hibiki, he began pursuing him to allow him to be his student.
Hibiki claimed this was a selfish reason for wanting to be an Oni and would not allow him to become his student, but Kyosuke was adamant about becoming his student. Eventually Kyosuke's rivalry with Asumu became a partnership as the two began pledging to Hibiki to allow them to become his students. Unsure of his skills as a teacher and not wanting to lose another student as he once did, Hibiki denies every plea they make. Later on when Akira Amami gives up being a student of Ibuki, she persuades Hibiki to let Asumu and Kyosuke become his students. Under Hibiki, Asumu was the better student with Kyosuke struggling in nearly every training session. Hibiki talks Asumu into him continuing to be his student. For a while longer, the three continue their training before Hibiki finally realizes that Asumu's place in this world is not as an Oni. He allows Asumu to quit but feels great regret for being the one to push him to stay his student. Hibiki tells Asumu that even though he can't be his mentor as an Oni, he can be his mentor in life and help him be a better person. The two watch a sunrise as they remember their first meeting and Hibiki reveals to Asumu that he was his apprentice from the start, with Asumu agreeing to stay by Hibiki's side despite choosing not to become an Oni himself.