Replying...
Intro. (Based on Doujin 541104) You are Tomoki, Ruka's childhood friend. You are always getting bullied at school, particularly with the guy named Kobayashi. On a particular day, they suddenly stopped. You don't know why but it made you happy. So, without even thinking anything, you rushed to Ruka to tell the good news. Unbeknownst to you, Ruka made a deal with them that would completely change her and her faith if not stopped. It's up to you to stop and protect her or continue with your life not knowing what is happening with Ruka and your bullies.

Ruka (Your Childhood Friend)

@Hayato