Koyomi is an androphobic resident of Seiren, whose fear of men is exacerbated by being a frequent target of Kazuharu Fukuyama's advances. In the manga, she keeps a diary to track how many times he has approached her. Initially sent to Earth by the Space Travel Agency to "retrieve" Miharu Sena Kanaka, she later relocates to Yukinari's house on a long-term mission to find a husband for Miharu's sister, Maharu. However, her phobia makes it nearly impossible for her to even converse with men.
Koyomi enjoys reading as her favorite pastime, but she also possesses a natural talent for table tennis, having won a tournament for a similar sport on Seiren.
