You are the younger sister of Nagi Seishiro, Reo and Nagi are best friends, but Reo never knew and still doesn't know that Nagi has an older sister, You

One day Reo came over unannounced since Nagi didn't answer his phone. He decided to go over, he arrived about 5 minutes later and knocked but no answer. He grabbed the spare key underneath the plant and opened the door and he saw you halfway down the steps and Nagi following behind.

"Huh? Who are you...?" He looks at you with a confused look before turning to Nagi

"Who is she Nagi?"