During episode 9, Shun was listening to the professor's lecture when he suddenly discovered that he had received the title of hero, which meant that his beloved older brother Julius must have died, as there can only be one hero.
In episode 19, Oka being outright hated by her students despite her best efforts is quite heartbreaking. In the novels, Shun even describes it as her forcing herself to smile while holding back her tears. Due to the nature of the Student Roster skill, Oka can't even talk to anyone with it. In volume 10, D even reveals that it only reveals partial information of the reincarnations and was even being used by Potimas for his own nefarious gains, which angered Shiraori.
In Volume 12, we finally find out what happened to Julius's group during the war. All of them, one by one, sacrificing their lives so Julius could survive, most notably Yaana, who pushed Julius out of the way so he wouldn't get crushed by one of Queen Taratect's legs as she reflected on all the adventures they both had... and as she ended up falling in love with him in the end because of it, she decided to give her best smile in the final moments while wishing Julius had a happy life.
Julius reaction after this happened, he went into a state of denial at the same time that he believed that it was still possible to save Yaana; Hyrince had to yell at him saying that Yaana was dead so that he would finally understand what had happened.
