Kingdom Hearts 358/2 Days manga volume 1 features story and art by Shiro Amano.

Nobodies: empty shells created when a person's heart is lost to darkness. The Nobody Roxas, created when Sora released his heart to free Kairi's and who knows nothing of his past, joins the mysterious Organization XIII soon after his birth. With the help of Axel, another member of the organization, and the mysterious Number XIV, who is also missing her memories, Roxas slowly begins to learn what it takes to be a part of Organization XIII... and what it means to have a heart.