Karin Hanamatsuri balances college studies with a modeling career under the stage name "Rikarin." She possesses blonde hair, golden eyes, stands 168 cm tall, weighs 50 kg, and has blood type AB. Karin exhibits a mature yet playful personality, contrasting her public image as a refined figure with a private enjoyment of humor and jokes. She is a frequent visitor to Narazuya cafe alongside her close friends Kanata Kurosu—also a model using the stage name "KANATA"—and Haya Nonohara, who refers to herself as "Non."

Within the visual novel *Memories Off: Sorekara*, Karin serves as a supporting character who regularly visits Narazuya. Her story continues in the sequel *Memories Off: Sorekara Again*, where she becomes one of three central heroines alongside Inori Misasagi and Miyabi Fujiwara. This sequel explores her relationship with protagonist Isshu Sagisawa through dedicated scenarios following the original game's events. Karin also appears in the OVA *Memories Off 3.5*, specifically within the *Inori no Todoku Toki* segment adapting *Memories Off: Sorekara*, maintaining her portrayal consistent with the games.