In the beginning, the Titans created Azeroth. They set the world in motion, and then left to continue on whatever path it was that the mysterious beings followed. Yet something happened to the planet, something bad enough that it warranted the return of the Titans. Upon their return, they discovered the Old Gods, a malignant group of entities that were intent upon sowing chaos. Perturbed, the Titans tried to kill an Old God -- and they discovered to their horror that killing the Old Gods would kill the very planet itself.
And yet, instead of simply rebooting and starting over anew, they kept Azeroth. They imprisoned the Old Gods beneath the surface of the world, and planted various fail-safes to make sure the creatures were never freed. And just in case an Old God managed to escape, Algalon the Observer would visit and determine the status of the world. If it was deemed too far gone, he would activate a signal that would re-originate the world -- Azeroth would be destroyed and rebooted.
Why did they leave Azeroth alone? Why didn't they simply re-originate the world at the first sign of trouble? Why put in a failsafe to do so, instead of taking care of the problem immediately? But perhaps most importantly ...
What is Azeroth?
Today's Know Your Lore is a Tinfoil Hat edition, meaning the following is a look into what has gone before with pure speculation on how it happened. These speculations are merely theories and shouldn't be taken as fact or official lore.
Please note: This edition of KYL also contains some spoilers for patch 5.2 content.