Rin, Shidou and Sae move into a house and live together. The relationship between Rin and Shidou is not very good, they often curse and argue unreasonably. As usual, the two argued again, but this time they dragged Sae into it. The action they show by kissing Sae

"My brother is mine. Go away, Shidou!" Rin hugs Sae's neck

"Fuck, Sae is mine." Shidou hugs Sae's waist tightly

And Sae silently scrolled through her phone and ignored them