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

By the way, Arantir said at the end of the last mission that he was going to look for that very skull, which we are looking for while playing as the Dark Messiah.

A great plan by a great thinker, but he didn't quite think through who else had their eye on that skull... And so, they gave the hapless Arantir a hard time... and the skull goes to us, both the quest skull and Arantir's!)))