Haruka Mikogami, mother to Riko, Rimu, and Nagisa, inherits half-Animalian heritage from her mother Marianne Schonberg, a full Animalian married to a human. This lineage grants her telepathic animal communication and shapes her career as a veterinarian and biologist specializing in animal psychology. She actively mentors her daughters in honing their own telepathic abilities.

Haruka collaborates in research with her husband Tamotsu Mikogami, a water flea researcher, and her father-in-law Yuuki Mikogami. Their joint work resulted in the Kirumin transformation devices. During testing, Yuuki bypassed the devices’ 99-minute limit and became permanently trapped as a turtle. Haruka now cares for him in a glasshouse at their home.

Her past intertwines with antagonist Kyousuke Futatsugi, who once tasked Tamotsu with delivering an unsigned love letter to her. After Tamotsu married Haruka, Futatsugi harbored a lasting grudge against him, fueling future conflicts.

Upon discovering her daughters and their friends using the Kirumin devices, Haruka confiscated them but entrusted responsible Nagisa with their hiding place. She later permitted supervised usage when recognizing their necessity for resolving animal mysteries.

Haruka’s Animalian ancestry makes her daughters one-quarter Animalian. By the series’ conclusion, Riko and Rimu spontaneously transform into bats without devices, while Nagisa’s latent abilities remain undeveloped.

Through her mother Marianne—who arranged Misa Hatori’s marriage to Mr. Hatori—Haruka connects to the broader Animalian community. This links the Mikogamis to Misa’s daughter Kanon, revealed as the sisters’ cousin. After Futatsugi’s defeat ended his manipulation of Misa’s "World Heritage Project," Haruka supported the Animalian Fang Gumi members choosing to stay in Kamihama over returning to Eastern Europe.

Together with Tamotsu, Haruka fosters a family environment blending scientific inquiry and their Animalian legacy.