Sana Miyama attends Soukai Academy and decisively intervened to save its Gunpla club from dissolution during her first year, when mass member departures threatened its existence. She actively recruited Ryusei Fudou as a partner to secure the club's future. Initially assessing her own Gunpla fighting skills as inferior to peers like Ryusei, Touma Aizen, and Rindo Kuzunoha, she grappled with self-doubt. Persistent engagement in battles and dedicated model building ignited her individuality and cultivated a deep passion for Gunpla. Her creations evolved from the Gundam Dianthus, blending Strike Gundam and Gundam X Divider components, to the award-winning Sanakapool—a radically modified Kapool lauded for craftsmanship. Later, her engineering expertise transformed a Gundam Areus into the Gundam Valkyrie, integrating parts from Gundam F91, Shining Gundam, and 00 Qan[T]. By Chapter 15, she succeeded Rindo as the club's captain after their graduation.

Sana regards Ryusei as her indispensable combat partner, their Gunpla consistently exhibiting synergistic designs and capabilities. She fiercely guards this partnership, visibly reacting against attempts to disrupt or supplant her role alongside him. Her development culminated in deploying the Perfect Strike Freedom—a Strike Freedom Gundam enhanced with Perfect Strike Gundam systems—during the GB Festa tournament. There, she openly dismissed antagonist Mahara Kentaro's vengeful grudge against Takuma as petty and irrational.

Cheerful, upbeat, and positive, Sana channels enthusiasm into diligent effort. Battle setbacks temporarily discourage her but spark renewed resolve to improve. She also demonstrates supportiveness, defending junior member Mizuki Sarashina from harassment and aiding her in conquering a fear of Gunpla Battle.