Budoko is an Aluminum Akikan born from a grape juice can, small but strong-willed. She speaks in a distinctive, often humorous way that can sometimes be difficult to understand.

Her core centers on her deep bond with her timid owner, Misaki Miyashita, a junior high student who initially feared making friends due to worries about conflict. Their close relationship features stargazing as their favorite shared activity and deepens to include a kiss, reflecting their emotional intimacy.

During the "Akikan Elect" conflict opposing Aluminum and Steel Akikans, Budoko faces grave danger. She is killed by the Steel Akikan Melon in one battle. Her fates diverge across adaptations: the light novels later revive her as RG:A, while the anime prevents her death entirely through Kakeru Daichi's intervention, causing Melon's attack to miss.

Later, the powerful antagonist known as the "strongest Akikan," capable of absorbing others' abilities, brainwashes Budoko. Controlled, she attacks Melon alongside another brainwashed Akikan, Yell. Eventually freed, Budoko joins Melon and Yell in a combined energy attack that defeats the antagonist.

Her development includes moments of vulnerability, like going missing during the strongest Akikan crisis, countered by resilience shown in her recovery and ongoing partnership with Misaki.