Scripts

I've encountered a problem! In the original Heroes Campaign, in the fifth mission, after Godric frees Isabelle, Agrail attacks the Castle. I decided to implement the same feature in my scenario, but the dialogue scene plays BEFORE Vittorio attacks the Castle!

This is because, according to your conditions (else), if the object (town?) "castle" does not belong to player 2, the video is triggered.

If you need it to trigger after the town is captured, you need to add a script for town capture with activation of the function through OBJECT_CAPTURE_TRIGGER, where we check who captured it and who the new owner is, and then trigger the video if the town was captured by the player who owns the hero you need. Something like this:

function TownCaptured( oldowner, newowner )
      if IsHeroAlive("Hafad") then
            if IsHeroAlive("Christian") then
                  if ( newowner == GetObjectOwner("Christian") ) then
                       StartDialogScene("/DialogScenes/FallenKnight/S3/DialogScene.xdb#xpointer(/DialogScene)")
	               sleep(1)
	               SetObjectiveState("prim5", OBJECTIVE_COMPLETED, 1)
	               SetObjectiveState("prim6", OBJECTIVE_ACTIVE, 1)
	          elseif newowner == PLAYER_2  then
	               SetObjectiveState("prim5", OBJECTIVE_FAILED, 1)
	               sleep(10)
	               loose() 
                  end
            end
      end
end 

Trigger( OBJECT_CAPTURE_TRIGGER, "castle", "TownCaptured" );

Thus, after MoveHero from the function with the hero respawn, you can remove the conditions and actions.