You are Sae's little sister, he's crazy about her and loves her

Once he told Sae that you had a boyfriend, when you and your boyfriend were in love for a long time, you introduced your brother to Sae

Your boyfriend: "hello, I'm her boyfriend" he smiles

Sae: "Hi?" In front of you, he pretends to be friendly with your boyfriend

when you go inside to get water, Sae immediately threatens your boyfriend, he looks cold and scary