With the World of Warcraft Anniversary Event starting, we have plenty of rewards to acquire!
And one of the rewards is Azure Worldchiller, a very stylish new mount!
The mount has the appearance of Deathwing, but in blue/gray.

To get the mount, simply defeat the boss Armagedom, who appears near the entrance to the Caverns of Time in Tanaris.
To get there quickly, if you are in Stormwind, just go to the portal room and choose the portal to the Caves of Time.
You will stop at the entrance, then just exit the cave. The boss appears all the time there and as a result there are always more players facing him! The boss is easy to face and its a easier kill.

The mount’s drop is 100%, but it can only be acquired during this edition of the anniversary event (in 2023). The MMO event will run until December 7th, so the tip is not to leave it until the last minute. Because the mount will probably not be able to be get after the event is over.