Oniichan to Issho

Sakura had lived with her grandma ever since her parents died in a car accident when she was three. When she turned fourteen, her grandma also passed away, leaving her alone. Just when she was about to give up hope having a family, out of nowhere, four guys claim to be her older step-brothers.

(Source: Esthétique)

Included one-shots:
Volume 1: Parallel to the World
Volume 2: Gakuchuu
Volume 3: Mahou no Tsukaikata (How To Use Magic)
Volume 4: Himitsu no Tobira no Kugurikata (How to go Through a Secret Door)
Volume 6: Santa no Iru Machi
Volume 7: Shirayukihime no Douwa (The long tale of Snow White.)
Volume 9: Kimi to Boku no Uta