Nobodies

In the Kingdom Hearts series, Nobodies are a group of enemies introduced to expand the series' idea of the heart. One comes into being when a person with a strong heart loses that heart to darkness: the body and soul left behind become a Nobody. Most take on malformed, inhuman shapes, but the members of Organization XIII keep their human forms because they had strong hearts and still remember who they were. Their insignia, an upside-down and incomplete heart, was designed to look like a splintered heart as a counterpart to the Heartless emblem. A Nobody can grow a new heart of its own over time, and Roxas and Naminé are treated as special cases because of how they came to be.