User blog comment:Argorrath/Treyarch releases a BO2 teaser video called "Origins" for DLC 4/@comment-3967954-20130807171131/@comment-5557418-20130807182727

Aug, have you remember the "diary" entries, or whatever? They were all marked by the original four, in 1917, and here, they look like them really young. The ending clearly shows some kind of WW1 scene.