User blog comment:Argorrath/Treyarch posts a message of zombies; possibly hinting to a DLC 4/@comment-67.169.165.224-20130805104048

If the Original Characters do travel back to try to stop Richtofen, or if it's an alternate universe, remember, there was a FOURTH experimental super-soldier, the Mexican talked about in Call of the Dead, so potential Richtofen replacement right there.