Its the super race of humans that colonized the planet waaaaaaay back when, called the Lemurians and/or Atlantians. Their remnants were hiding under water after the lizard war. Drugged out and pissed off that theres no more lizards to kill, they decide to wipe out the slave race that the lizards used to use (IE normal humans) to mine gold. Since normal humies are seriously fucking the world up, and they are no longer slaves, the atlantians see no purpose for the normal humans, and they want their planet back.
OR!
Its the Khazarians. They used Atlantian/Lemurian technology they found in the abandoned underwater bases to forge an elite strike force to attack all the world's major powers. After losing their country to the old Russia back in the early 400 AD era, the Khazarians made sure to keep on making life miserable for all of mankind, by infiltrating every major world power over the generations. They wish to take complete control of this planet, all in the name of their god, Baal. Hail Satin! (aka Baal) Yuri probably knows about their secret, and might have ties to them. The Khazarians still have a grudge against Russia.
- - -
naw, seriously, its a breakout faction from at least the Soviet side, if not all of the sides. That portal looking device in the soviet base in the video? Well it could be a power generator of some sort, or indeed a portal.
I like the Shark logo 'cause, the shark is kind of the ultimate predator of the sea, and has to keep moving and killing in order to survive. Your little anger is but a seaspray of blood in the endless ocean of this worlds killings! The shark churns on thru the blood ocean, and rips all other creatures apart.
This 4th faction comes about, after a certain bunch of groups across all other factions, discover something very powerful. A new kind of power source? A secret answer to Yuri's threat?