The End of Azeroth that only happens if nothing disturbs the world soul growing within, allowing the Titan to emerge and tear the world apart in the process, killing any life that might have been thriving upon its surface. The knowledge that this would, without a doubt, come to pass combined with the whispers of the Old Gods ensures that Nozdormu goes Murazond every time. The Titans empowered the dragons to protect the planet with the intention that it would one day all end.