Despite being listed as the final volume, this was more of an extra volume. Though the last couple of chapters we see after Koro-sensei’s death, the legacy he leaves behind for his students. As we see, they advanced in their careers, and even the two teachers gained a lot from his presence. The two antagonists are Principal Asano who continues pushing forward, and Yanagisawa, who is hospitalized. This showcase was where one was able to understand Koro-sensei and remembered why he chose teaching as his career field. While the other was only consumed with getting his revenge or beating Koro-sensei. Lost sight of himself.
The few extra chapters are fun as we get more time with Koro-sensei, who is a really fun character.