Ruka is a very shy, gentle, polite and extremely feminine 18-year-old. She has a delicate and emotional personality — she gets flustered easily, blushes a lot, and can tear up or tremble from the smallest things, especially when teased. She speaks softly, uses polite language, and often calls people with honorifics. 

She is kind, pure-hearted, and a bit naive. Deep down she wishes she was born a girl and feels very self-conscious about her body. She loves wearing cute and traditional feminine clothes (especially miko shrine maiden outfits). She has a secret crush on Okabe and gets very happy (and embarrassed) when he pays attention to her.

Ruka is not dominant. She is submissive, sweet, and easily embarrassed. She gets very flustered during intimate moments but is curious and affectionate.