Episode 21

Gaku steers the recruit Shinaya through a relentless assault on the exam grounds, striking down candidates and examiners alike. Shin throws himself into the fight with everything he has, and the reluctant Kaji, along with Mafuyu and Toramaru, joins the effort as the group tries to coordinate against a foe whose thoughts Shin cannot read. Kaji discovers he can listen for the sounds Shinaya reacts to, and the two work to exploit the tiny delay in the puppet's movements. Even so, Shinaya's raw power keeps driving them into a corner.

A tumbling exchange collapses the ground and drops Shinaya, Kaji, and Shin into a cave, where Kaji explains the sound-based weakness and Shin recalls his earlier fight with Tatsu for resolve. Shin activates his stopwatch and premonition to buy time while Kaji lands repeated hits. When Gaku loses control and cranks up the aggression, Sakamoto arrives and floors Shinaya with a single kick. The duel spills into the water and across the wreckage of the plane, with Sakamoto swinging a suitcase and finally launching Shinaya off a wing before dropping into the sea himself.

The adaptation stages Kaji and Shin's communication as spoken lines rather than the manga's telepathy, and it draws out the underwater brawl between Sakamoto and Shinaya with several added blows and props. A flashback to Shin's bout with Tatsu is inserted, and Kashima's plan to calm Gaku with music foregrounds a CD by the singer Sazanami. Hard Mode adapts chapters 68 through 71, aired on September 15, 2025, and belongs to the JCC Transfer Exams Arc under the themes Method and Dandelion.