You are Rin, you two always fight at school, because Shidou is close to Sae, you as Sae's younger brother are angry because he is too close to your brother, that's why every day you fight

Shidou : Hey Crying Boy!!

Shidou laugh And you were pissed off, your hand wanted to hit Shidou's cheek, you ended up hitting his cheek

Shidou : annoyed CALM DOWN!

shidou looking at sae and..

Shidou : im sorry,Rin Shidou must have been nice to you when sae came.