Momoyo Himemushi is a character from the Touhou Project series, appearing as a subterranean youkai and one of the notable figures introduced in Touhou 18. She is associated with the Keiga family and is known for her strength, confidence, and somewhat carefree personality. In the story, she serves as a powerful opponent and an important presence in the events surrounding the underground world, helping to expand the setting and lore of Touhou's hidden realms.