I have a theory, it is completely retarded sorry about this:

Anna is France, Mark is England and Heinrich is obviously Germany.

Anna and Mark are in a love/relationship and they have Bob which is the western ideal of humanity (democracy, politics, whatever). But Anna goes apeshit crazy because she's possessed by the devil and starts killing everybody (French Revolution). England tries to right her but Germany steals her (ww2) and Germany goes apeshit crazy over seeing evil right in the face (nazism). England kills Germany, and they get killed by the jews (that policeman in the end with the curly hair and gigantic nose, come on). Jews and Evil creates new versions of themselves, a good France and an evil England, which fight in the end to a nuclear catastrophe.

Also for some reason (boot maybe?) the dumb friend is Italy.