Cloven

The Cloven have not appeared in the story of Resistance: Fall of Man, but appear as an unlockable skin in the multiplayer mode. They will also be an enemy in Resistance Retribution.

A British soldier guesses that they probably turn into Slipskulls (a type of Chimera), although due to how the conversion process works (the strain is determined by the number of humans used), it is likely that they are used to create a wide variety of Chimera. They appear to be enemies of both the Chimera and the Euro-American forces, due to their hostility towards both.

One theory is that the Cloven are a group of infected(with the Chimeran virus) Humans from Russia. They have no alliance other Humans or Chimera. They are Cannibalistic eating the dead bodies so the Crawlers do not infect them(This is a FACT proven by an Intel doc). Sometimes when the Cloven are found dead they have the picture of their leader in their mouths(This is a FACT proven in an Intel Document). The leader has been confirmed to be one Dr. Malikov). However, as one Intel Document discribes, Cloven who are captured by Chimera will bite their own veins to kill themselves, rather than be infected. It is possible then that Cloven can be infected further by the Chimeran virus. The Cloven appearances are mostly the same. Pale, bald. They were a uniform similar to the British but Gray and wear Helmets with the Russian letter Д (D),and sometimes a bandanna to cover their faces. The Cloven have been known to make Inhuman noises.

Project Abraham insights
It has now been revealed in the Project Abraham website that the Cloven are in fact a strain of Chimera, but they are more human, have retained their individuality, and were in fact created by one "Malikov", and are also controlled by him.