Suruga, the main character of Suruga Monkey, is Koyomi's underclassman, ace of the school's basketball team and one of Hitagi's acquaintances from back in junior high school. Immediately after she entered senior high school, she became aware of Hitagi's secret and was threatened by her, just like Koyomi was. She's an admitted lesbian, fujoshi, lolicon and masochist.

Back in elementary school, she inherited what she thought was a Monkey's Paw but was actually a Rainy Devil from her mother. She started stalking Koyomi after she discovered he was dating Hitagi. She becomes friends with Koyomi and Hitagi after Koyomi rids her of the Rainy Devil. She also has been growing her hair longer since. Her next story was revealed to be Suruga Devil.