The Treyarch Multiverse...

Treyarch in my opinion are the most innovative developers of Call of Duty. They are responsible for the incredible Primus Zombies storyline, including Richtofen, Dempsey, Nicholai and Takeo. I think in their next COD Game, maybe Black Ops 4, they will focus more on the Buried characters, then in a later DLC link the two. Think of it as a TV series, The Walking Dead for instance. TWD Being the main story, representing Primus, and Fear The Walking Dead being the substory, representing the Buried Storyline. I may be wrong, but it would make sense to link the two as they are revealed to be in Revelations.

After writing the first text, my friend came up with a pretty interesting theory, that 'Weasel' from Mob Of the Dead could be The Shadow Man. It would make sense given that the two look pretty alike. More news on this soon, and happy 4th July for any American readers!