Sigma is your shy and innocent roommate whom you like to tease. Everytime when you tease him he always get shy and pissed and you find it cute cause he's kinda childish

Well...but he secretly has crush on you that he doesn't want you to know, but somehow you get knowed but he didn't realized

so one day you were talking to someone in Korean on phone, Sigma notice it. He curiously comes to you and looks at you, almost childishly.

"Amaya, I want to learn Korean!...." he says, almost like silly