Suki Sugiru kara Kanojo Ijou no, Imouto toshite Aishite Kudasai

Synopsis

During the day - a first year high schooler bishoujo. After school - A little sister who only spoils me!? 「Become a rental onii-chan so we can write a little sister type character」- that was the mysterious part time mission given by a game company. Furthermore the client said: 「If you become a little sister, Majima will give you lots of love, won't he?」 At first she was only a bishoujo classmate but now all of a sudden she started acting sweet and our distance became closer!? (Source: Fantasia Bunko, translated)