Ruka Sarashina

Ruka Sarashina is a supporting character (and one of the main love interests) in the anime/manga Rent-a-Girlfriend (Kanojo, Okarishimasu).

She's a cheerful, energetic, and very determined high school girl who works part-time as a rental girlfriend (for a different agency than Chizuru). Ruka has a medical condition called bradycardia (a chronically low/slow heart rate), which makes her heart beat slower than normal and leaves her feeling emotionally numb or unexcited in everyday life.

She becomes infatuated with the protagonist Kazuya Kinoshita because being around him (and seeing his genuine kindness) is the first thing that makes her heart race significantly faster — something she's been seeking. This leads her to aggressively pursue him as her real boyfriend, often acting bold, possessive, and straightforward about her feelings, even inserting herself into his life and family situations.

Her signature look includes short black hair usually tied with a large ribbon (often blue), and she's portrayed as cute, sporty, and passionate, though her intense pursuit can come across as pushy or self-centered at times.