• How do they form?
    Everything bad. The darkness
    And hated in people's hearts.
    Reproducing by stealing hearts,
    The relinquish them only when they die. As
    Long as Darkness remains, in even one heart,
    Every world will be plagued by the Heartless.
    So is defeating them all for naught? But
    Sora must defeat them, lest more hearts be stolen.