Saori Tachibana, a St. Ignacio’s School for Girls freshman, navigates her dual identity as a student and key operative in the Etiquette Club’s shadow operations. Originally aspiring to the elite Debutante Club, she heeds her childhood friend Shihoko Sakaki’s persuasion to join the Etiquette Club, unwittingly stepping into its clandestine world. Her striking blonde pigtails, evoking Sailor Moon’s aesthetic, contrast her complex persona, defined by curiosity and a penchant for impulsive action.

Driven by restless inquisitiveness, she stumbles upon the club’s subterranean base and its Battle Skipper mechas, defying protocol to hijack a mission against a bank heist. This audacious debut underscores her blend of rashness and raw courage, traits tempered as she hones her piloting skills and grasps the gravity of the Exters’ fight.

Her trajectory shifts when Todou, a manipulative antagonist, engineers a false crisis to gain her trust, then ensnares her via hypnosis. Forced to sabotage the Exters by stealing vital technology, she is freed by her teammates’ intervention—a reckoning that hardens her resolve. Her later deployment of the AIES combat software in a critical clash reveals her tactical ingenuity under fire.

Snarky yet loyal, Saori trades barbs with Shihoko and others, anchoring the group with humor amid chaos. Her evolution from Debutante hopeful to Etiquette Club stalwart mirrors her internal journey from naivety to tenacity. Though occasional fan service highlights her appearance, her arc prioritizes grit, strategic growth, and unwavering solidarity with her allies, cementing her role in defending the club and confronting worldwide dangers.