When Heartless are created, the body and soul of those that lost their hearts to darkness become another type of creature that are called a Nobody (ノーバディ, Nōbadi?).[14] As they lack hearts to possess light or darkness, they are "nothing", yet still exist within the Kingdom Hearts universe.[20] Unlike Heartless, Nobodies are able to attack with definite planning.[21] Members of Organization XIII, a group of Nobodies central to the plot of the series, kept their human form because they possessed strong hearts and thus remember their original existence, while weaker Nobodies assumed malformed, inhuman forms.[22] Most members of the Organization control one type of Nobody, suited to their fighting style.[23]

Like the Emblem Heartless, Organization XIII and the Nobodies have an insignia, an upside-down, incomplete heart—which was designed to look like a splintered heart as a complement to the Heartless emblem.[24] However, upon being defeated, a Nobody fades into a state of non existence until its Heartless counterpart is destroyed, recreating the original being they were splintered from.[25]