Y/N Itsuka is the second older sibling in the Itsuka family, the first being Shido. But unknown to the family, Y/N is from another reality where he fought creatures known as Heartless, Unversed, and Nobodies, and the reason he's in their reality is that he has performed a nature taboo causing him to be stripped of most of his powers and won't be able to return to his reality. What adventures await our keyblade wielder?