Yoshiteru Zaimokuza studied in Sobu High School's Class 2-C, having endured bullying before high school over his large build and chuunibyou tendencies—persistent adolescent delusions of grandeur often called "eighth-grade syndrome." He stands notably tall with a slightly overweight frame, grey hair tied in a short ponytail, and wears glasses. His distinctive brown trench coat layered over the school uniform and black fingerless gloves often leave him appearing sweaty in any season. Zaimokuza speaks with grandiose, narrator-like inflection, refers to himself in third person, and immerses himself in fantasy role-playing scenarios. He exhibits fervent passion for historical shoguns, magic, video game development, and light novel writing—though his writing faces consistent criticism for poor quality. Aspiring to become a famed light novel author, movie writer, or marry a voice actress, his eccentric conduct earns widespread perceptions as weird, creepy, or gross, worsening his social isolation. Yet he withstands criticism from peers like Hachiman Hikigaya and Yukino Yukinoshita, retaining enthusiasm for creativity. His chuunibyou persona partly acts as a defense against past bullying and ongoing rejection. His bond with Hachiman started in their first year when gym class paired them as partnerless loners. Though Hachiman routinely denies their connection, Zaimokuza views him as a friend. He regularly visits the Service Club seeking feedback on light novel drafts, enduring harsh critiques while valuing the interaction. Key moments include accompanying the club to a maid café despite lacking experience and struggling to converse with staff; collaborating with Ebina Hina on Athletic Festival events, contributing the "Chiba Shouldertop Engagement" concept—during which he revealed unexpected strength by executing the "Zaimokuza Crusher" to topple a rival pole and reaching the Judo finals alongside Hayama and Hachiman; having his original script chosen for Class 2-C’s Cultural Festival play; and confronting harassment from the United Gamers club over his creative ambitions. He defended his passion by declaring, "I write because I love it," impressing even Hachiman with his sincerity. Others nickname him "Chuuni-chan" (Yui Yuigahama, Komachi Hikigaya), "ZaZaMushi" (Ebina), and "Snowflake" (Komachi). He envies popular students like Hayato Hayama and struggles acutely when interacting with girls. Subtle development occurs across his school years: he briefly considered game writing but abandoned it upon learning companies would own his work rights; chose science over liberal arts in his third year, citing fewer female students and greater comfort with technical subjects despite his authorial dreams; aided Hachiman’s manipulative tactics during the Student Council election by creating fake social media accounts while voicing discomfort with the scheme; and during a career crisis, reaffirmed his commitment to light novel writing, inspiring Iroha Isshiki’s student newsletter initiative. Occasional vulnerability surfaces, like recognizing Hachiman’s hypocrisy about their friendship or expressing loneliness. His dedication to writing remains a constant throughout all media.