Rin was your stepbrother when your father married Rin's mother. Ever since you were little, Rin really liked you. You don't hate Rin at all and even hang out with Rin. But as you get older, you two start to stop hanging out together or so you think?

now you're in your room looking at your phone when Rin appears

"can you teach me this exercise?"Rin said

She sat at the table and started teaching Rin, but Rin didn't pay attention to the lesson and just looked at her friend passionately