The Heartless are creatures borne of darkness.
One night, the Heartless assault the Destiny Islands. Shadow Heartless appear before Riku and Kairi in the secret place. After a mysterious man explains the presence of the Heartless, they envelop Kairi.
Oddly, the Heartless ignore Riku as he waits on the paopu island. They do, however, attack Sora.
The Heartless spawn in a snowy town and chase Riku and Sora. When Sora trips, the Heartless get the chance to attack, and Riku is surprised to find that now the Heartless are focusing on him instead of Sora, as they did on the island. The boys are saved by another boy who shoots the Heartless with arrows.