We now seen in the season finale the devastating impact of the dead dragon on the Wall. The dead are marching forward, and the more they kill in the way the more powerful is their army. However...they have a hugh weakness - a single point of failure - the night king! If he will be killed then all the dead get killed as well, since he is the originator of the zombies. There are still 2 live dragons, and the night walkers can be killed by fire - so that should be the strategy to end this war. I predict that as the ending of the army of the dead.