Episode 36

Secret Identity Time is the thirty-sixth episode of the Assassination Classroom anime and the fourteenth episode of Season 2. It first premiered in Japan on April 7, 2016.

Summary
As the end of the second semester draws near, Kaede Kayano launches a surprise attack on Korosensei using tentacles she had implanted in herself for the whole year, and wants to kill him for the murder of her elder sister Aguri Yukimura, the former teacher of Class 3-E. As the class try to deal with the sudden revelation, Kayano thinks back to how she planned her revenge before challenging Korosensei to a fight that may cost her own life.

Plot
After the school play the class discuss their success. Sugino is worried that his performance as the lecherous husband has been too perfect and believes that Kanzaki will be scared of him despite everyone's else positive comments. Kanzaki however also comments positively, which Sugino considers switching from baseball to acting. Meanwhile Kayano beckons Nagisa to the store shed, where she has accidentally spilled the contents all over the floor. The two start to clean up, soon joined by Korosensei who noticed their absence in the classroom.

All three reminisce their past moments and successes, Kayano in particular. She soon pulls back her hair, and tentacles begin sprouting from the nape of her neck. Nagisa, whose back was turned until that moment, begins to be surprised, as Kayano starts attacking an equally shocked Korosensei. Kayano blows the floor open, revealing a pitfall trap, musing that of all the plans and tactics used against their teacher, a simple trap was the most effective. Korosensei plunges down into a pool of anti-sensei BBs, unable to get a grip on the walls as Kayano's tentacles predict every movement. Korosensei is forced to concentrate some energy to blast his way out of the pitfall trap and Kayano instinctively recoils in defence, allowing him to escape back to the surface. The whole class rush outside following the commotion as the slightly bruised Nagisa emerges out of the store shed. Kayano follows afterwards, slightly disappointed that she had underestimated her target, and the class immediately sees the change in appearance and personality. When Korosensei, still reeling from the surprise assault, asks what had happened to Kayano, she merely replies wanting vengeance for his murder of her sister Aguri Yukimura. Kayano also states she will notify him of their next battle before departing with her tentacles.

At the same time in an undisclosed location, Shiro discusses how surprised he had been to see an unexpected face the first time he arrived at Class 3-E. He soon investigated this student and discovered that Kayano is in fact Akari Yukimura in disguise, and that she had somehow acquired information as well as a vial of the tentacle weapon which she planted into herself. Shiro further states that with her acting abilities, she is the most capable and qualified of her classmates to be an assassin. Meanwhile the class are still reeling in shock of Kayano's sudden turn. Mimura notes that she looked vaguely familiar to him and found that she was a prodigal child actress who took a temporary break from her profession. Nagisa himself muses how intelligent Kayano really is, hiding her own bloodlust by hanging around with Nagisa (the student with an equal amount of bloodlust) and not getting too close with everyone else. He also deduces that Kayano's pudding plan had been a dummy attempt to avoid any suspicion that she isn't as active in the class's assassination plans. Isogai soon demands that Korosensei reveal his past and why Kayano accuses him of murdering their previous homeroom teacher Aguri. In light of Kayano's attack, Korosensei agrees to tell the class, but not until Kayano returns. He afterwards receives a message from Kayano, challenging him at a park at 7pm.

As evening draws near, Kayano reflects on the past year, as well as when she had last seen her sister alive at a cafe. While waiting to meet up with her sister, an explosion at her workplace occurred. Kayano easily made her way through the rubble to find a tentacled monster standing beside Aguri before leaving. Kayano sees her sister lifeless and a note saying that the perpetrator will be teaching at Kunugigaoka Junior High. She also took the vials without thinking and researched it. In preparation for her revenge, she transferred to Kunugigaoka on her first try and immediately destroyed Chairman Asano's laptop to get herself in Class 3-E. After changing her hairstyle and dyeing her hair green, as well as implanting the liquid into herself, she soon enters Class 3-E and meets Nagisa for the first time. Deciding she can hide among him, Kayano changes Nagisa's ponytail to the signature pigtails. Shiro soon interrupts the flashback, accosting her of not waiting on him to activate his plan. Kayano retorts that he abandoned Itona and that she prefers to work alone before departing. Shiro muses that she should not have acted so coldly to her big brother.

At 7pm Korosensei and the class meet Kayano at the park. They try to dissuade Kayano from fighting any further but she refuses to listen, and even claims that everything they went through the whole year had all been an act when Nagisa asked her. She continued to portray herself as fragile despite her bloodlust tempting her during the  kidnapping, Takaoka and the Reaper incidents. Although warned that it is not worth sacrificing her life to kill their target, Kayano does not plan on dying, only killing her teacher, and begins attacking Korosensei. Itona sees that just 15 seconds into the battle Kayano's tentacles were already taking over her consciousness, and she will die if she does not stop. As Korosensei continues to defend himself, Kayano's sub-consciousness begs him to help her.

Differences between Manga and Anime

 * When Kayano blows open the hole for Koro-sensei to a pitfall trap, the trap wall is purely soil. In the manga the walls were covered by thin steel.
 * Nagisa had bruises and scratches, and had to be carried out by Isogai after Kayano activated her trap. In the manga, he was unscathed and did not need anyone's support.
 * The class ground was shaken when Kayano makes a hole for a pitfall trap while in the manga the ground was shaken when Koro-sensei digs his way out.
 * When Kayano first met Chairman Asano in his office, she instantly broke his laptop with a hidden baton. The manga instead has her breaking Asano's possessions with her own hands
 * Ono was present in the office instead of another teacher in the manga.
 * When the class watches one of Kayano's TV shows, they view it through each of their cellphones. In the manga they watch it through Ritsu's interface monitor.
 * When Aguri and Kayano talk about having the same genes, they were at a cafe. The manga depicts them discussing it while walking together.