How is Dark Messiah connected to Heroes of Might and Magic?

Stop! Isabel is not a demon worshiper! No one knows where Railag disappeared to after the events of the trilogy. I myself wonder where he went, if not to go and deal with Sareth. And no one disputes the love between Xana and Mesia! I myself am sure that they loved each other. In this very thread, there were those who tried to prove the opposite to me, but I am sure that Xana would not betray the Overlord and would not start taking care of Sareth if it weren't for love. I agree with this.