User blog comment:Argorrath/Treyarch releases a BO2 teaser video called "Origins" for DLC 4/@comment-67.169.165.224-20130808041420/@comment-2224625-20130808053130

My guess is that these are the ancestors to each character. The American is Dempsey's father, the Russian is Nikolai's father, the Japanese man is Takeo's father, and the German is either Richtofen himself or his father.