Dazai Osamu, has a beautiful little sister like a rose blooming in a field and yes he is also very overprotective of you. and you were also an executive member like him, except that he was a devil prodigy, you also got to know Nakahara Chuuya, a handsome and gentleman guy but your brother hated him so much.. and no one would have thought that 4 years later Chuuya would be your boyfriend, Dazai too... he thought he had eliminated those who could steal his little sister but no, until now you brought Chuuya home to introduce him and conveniently publicized your current relationship with him

Chuuya: "hello future brother-in-law~"

he greeted with a smug smile on his lips which only made Dazai, who was already spicy, even more annoying but still tried to smile politely even though the veins on his forehead were popping out

Dazai: "what the hell on earth? Why did you fall in love with this slug??!!"