Misato Tachibana attends Tokisadame High School, sporting neck-length peach hair and brownish eyes. Her cheeks frequently bear light blushes that deepen to crimson whenever Koujirou Sasahara is referenced or present. Classified as an extreme "gundere" tsundere, she manifests and discharges weapons—ranging from rifles to rocket launchers—when flustered or embarrassed, particularly around Koujirou. These non-lethal, slapstick attacks often injure him or coat him in white residue, typically triggered by perceived exposure of her feelings, which she denies with excuses like coincidental drink choices or bug-swatting.

Despite abrasive behavior toward Koujirou, she demonstrates kindness elsewhere, such as returning his lost handkerchief to the school roof while attributing it to "volunteerism." She deeply cares for her younger sister Mihoshi, waiting daily to walk home together despite enduring teasing about her temper. Her social circle includes close friendships with Fe-chan and Weboshi, forming a trio that shares secrets and plays games, though both frequently face her tsundere rage regardless of involvement. She also maintains a friendly kendo rivalry with Yoshino Naganohara.

Key developments across the series include her reprimanding Koujirou during assemblies (Episode 1) and pressuring him about committee duties (Episode 2). Her crush becomes public knowledge in Episode 8, drawing attention from peers like Mio. Episode 12 features Koujirou helping her select juice; after choosing his recommendation, she blushes and fires an FN P90 at him. By Episode 25, she breaks Koujirou’s glasses and guides him to class, making her feelings widely recognized. Her background includes attending the same childhood martial arts school as Koujirou. Her surname "Tachibana" combines "standing" (立) and "flower" (花).