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

The assassination of Nicholas was not the goal of either of them... Their goal was Isabelle... Nothing else held them in Griffon! Nicholas himself got caught in the crossfire... That's all... Agrael was supposed to deliver Isabelle to Shio! Initially, Grol was supposed to do it, by attacking Ashan... But when Grol died, Agrael decided to take on the task himself... And that's how the meeting happened... And Xa-Belehu benefited from throwing Agrael to the wolves... And he needed to complete the mission to prove his "loyalty" and lull the Overlord to sleep!