Omae wo Onii-chan ni Shite Yarou ka!?

One day, Yoichi who grew up while not knowing his parents has received the news of his father's death. His father left behind a testament——which said he is to pick only one out of five 'little sister candidates'?! "...I don't want to work, I want to laze around together with Onii-chan." (By Serene)