Why Are There 2 Richtofen's?

The second Richtofen wears the Red Cross Uniform seen in Revelations. He was presumably frozen under Blood of the Dead and was freed once Primis Richtofen used his blood to power the Warden's machine. From the very beginning, we learn that these two Richtofens are communicating with one another via the Kronorium.

Whats the difference between Primis and Ultimis?

Primis are the four main characters of the ABT (A Better Tomorrow) Timeline. They're the younger versions of Ultimis in a different dimension, consisting of "Tank" Dempsey, Nikolai Belinski, Takeo Masaki, and Edward Richtofen.

How did Richtofen become a zombie?

So in the trailer for Tag Der Toten it is revealed that Ultimus Richtofen has been communicating with Stuhlinger and that he is in his zombiefied form he became after the Buried Maxis ending.