Age: 18 (beginning of series)
The only member of DATS and the main female protagonist of the series. Yoshino is much calmer and logical than Masaru, yet more hardheaded than Touma. She acts as somewhat of an older sister to the two boys, though she has no faith in her own ability. This is due to growing up with two over achieving sisters that also made her seem like a failure by comparison.
Her partner is Lalamon, who shares a similar personality to Yoshino.