You just killed the last unit of enemy hero's army and as it falls down epic cinematic kicks in showing your hero charging the enemy hero for the kill, depicted as he was in the battle, tears or blood and carrying whichever weapon you equipped him with.
This is actually something like a sync kill in Dawn of War 2
Each faction and class(might or magic) would get a different looking one. Can you imagine what would be the result if you give this job to these guys. I can't even conceive how great it would be.
It could either be a cinematic like battle cinematics are now, or it could be from unchanged perspective like in Dawn of War 2. Mage classes would kill from where they stand, each one in different way.
Haven mage would focus a beam of light slowly burning enemy hero to a crisp, Necro mage would summon specters which would encircle the enemy hero in a whirl, lift him from his mount while he struggles and tear him to pieces....you get the idea. Might heroes would get awesome melee moves each depicting the essence of its faction.
I would really pay good money for this DLC, what do you guys think? If a real time strategy game like Dawn of War 2 has this why not here...