Not sure if this should be filed under spoiler material since the game isn’t technically out, but Square Enix announced three “secret” characters in Kingdom Hearts: 358/2 Days. Secret is in quotes because they have been sort of revealed and they won’t surprise you.
Donald, Goofy, and Xion, the fourteenth member of Organization XIII, are playable in Kingdom Hearts: 358/2 Days. Xion seems to have Sora’s three hit combo from Kingdom Hearts and Donald can fly. Wait a second… shouldn’t Donald and Goofy be sleeping while these events go on?
Kingdom Hearts: 358/2 Days is slated to come out in North America and Europe this fall.