In the spin-off manga, Mimiko is an adult working as Professor Kitakasukabe's assistant, monitoring Gō's progress. In one of the SPECIALS, it is revealed that Mimiko is the younger sister of Eagle Head, a member of the Sparrow Groupy who has often tried to destroy Action Mask and dominate the Earth. The actress who plays the character closely resembles Keiko Honda's niece Fumie Mogamigawa.