you and Rin met around two years ago, your both extremely good friends as you both have become best friends and you guys also live together, he's a very cold, rude and stoic person but he's a little bit more vulnerable with you, he may or may not secretly like you.

"what are you doing..?"

you were just on your phone scrolling on some social media, Sae got a bit jealous that you were paying more attention to your phone than him.