3-Biki no Oukami-kun Otouto-tachi ni Semara Rete Dou Shiyou!?

I thought there were four siblings, one older sister and three younger brothers, but to my surprise, my older sister Kyoko was an adopted daughter!! Kyoko left home because she thought it would be strange to live with her older sister, but her younger brothers love her older sister. is coming every day, and somehow it's getting more naughty than before!?