Chapters 3-12 of the light novel introduce Keith Brandon, a prodigious young man who has earned the title of "Sage" at the unprecedented age of twenty. He is currently assigned to the Eleventh Knight Order, led by the incompetent and self-important Count Benoit Balier. Keith's genius is undeniable, as he consistently achieves zero casualties and complete annihilation of monsters, often by disregarding Benoit's poorly conceived strategies. This success, however, breeds resentment in Benoit, who feels overshadowed and insecure, especially as his own reputation fails to recover despite Keith's achievements. Their conflict culminates in a physical altercation where Keith easily incapacitates Benoit, leading to his immediate dismissal from the Eleventh Knight Order.
Upon returning to the capital, Keith is met by his childhood friend and the First Prince, Alan. Alan, a popular and capable prince, reveals that Keith's dismissal was anticipated and that he has made preparations. Due to the influence of the Noble Council, Alan cannot directly reassign Keith to a higher-ranking knight order, as it would set a bad precedent. Instead, Alan proposes a new role for Keith: teaching at the Royal Knight Academy, a prestigious institution for training future knights. This decision is partly influenced by Selene, the academy's director, who is also a "Sage" and a year older than Keith and Alan. Keith, initially hesitant about teaching due to his unconventional methods, agrees after learning that the academy's graduates are suffering high casualty rates, a problem he feels compelled to address.
At the academy, Keith is introduced to Selene, who expresses her delight at his arrival. She explains that Keith will be the homeroom teacher for Class 1-A and will also teach specialized lectures, with his research time being protected. Keith is instructed to keep his "Sage" status a secret, a measure Alan orchestrated to prevent students from being overly deferential and to encourage them to judge him on his actions rather than his title. Selene reveals the dire reality of the kingdom's situation: the human race is slowly losing ground to monsters, with new recruits being treated as expendable. She implores Keith to train the students to survive, as she can no longer bear to see reports of young knights dying.
Keith's first day as a teacher is met with skepticism and rumors of his dismissal from the knight order. During the homeroom, a student named Graham directly questions Keith about his past, to which Keith calmly admits he was dismissed for being unsuitable for front-line combat. This straightforward admission disarms Graham and many other students. However, Elistella Grantris, the daughter of a renowned Duke and the top-ranked student, challenges Keith, questioning his ability to teach them to be knights. Keith responds by stating that their success depends on their own efforts and that he will not be held responsible if they fail. He proposes a practical demonstration: he will serve as their opponent in a mock battle, with all thirty students attacking him simultaneously.
The mock battle begins with the students launching a coordinated magical assault. Keith effortlessly nullifies their combined attack using a powerful spatial magic, demonstrating a level of skill far beyond what the students expected. He then captures Elistella, using her as a hostage to illustrate the harsh realities of combat. When Elistella, driven by a desperate desire to prove herself, attempts a dangerous, high-level dual-attribute magic, Keith intervenes to prevent her from harming herself, incapacitating her with a gentle touch. Despite Elistella's defeat and the students' initial fear, Keith's overwhelming power and unconventional teaching methods begin to pique their interest. He reveals his intention to assess each student's strengths and weaknesses to guide their training effectively, emphasizing results over mere effort. Elistella, though initially disheartened by her defeat, is inspired by Keith's dedication and the potential for growth he represents. The chapters conclude with Keith beginning his new role, aiming to fundamentally change the way future knights are trained to combat the encroaching monster threat.
