Quick answer — Mia Regina performed 1 anime theme, including "Tsukiumi no Yurikago" from The aquatope on white sand.
Mia Regina performed the anime theme songs "Tsukiumi no Yurikago" (The aquatope on white sand).
Mia Regina's first listed anime theme is "Tsukiumi no Yurikago", the ending of The aquatope on white sand.