病んでる義妹に寄り添ったら、俺がいないと生きていけない体になっていた件 (Associated Names)

“I’m all you need right, Nii-san?” My parents remarried and I got a step-sister two years younger than me. However, my step-sister became a shut-in after being bullied in middle school. In order to get my shut-in step-sister to open up to me, I, as her older brother, made a lot of attempts and as…