Luka Urushibara

Ruka Urushibara (漆原るか, Urushibara Ruka) is a bishōnen who looks strikingly like a girl and even wears the garment of a miko despite being a boy. He is a close friend of Mayuri and is often asked by her to try on her cosplay costumes. He has strong feelings for Okabe because he protected him from stalkers in the past and he does not care whether he is a boy or a girl; however, Ruka hides these feelings because he is a boy.

Due to Okabe's intervention in the form of a message sent into the past to Ruka's mother, Ruka experiences being a girl until he decided to return to being a boy after witnessing the consequences of her wish of being a girl.