It's about time Deathwing got what was coming to him. World of Warcraft's "Hour of Twilight" update lets players go toe-to-toe with the big bad dragon himself but first you'll have to do a little time traveling to claim a relic that'll defeat Deathwing proper.
"Hour of Twilight" brings in a couple of new dungeons and raids along with various tweaks for all classes. Transmogrification and Void Storage are also introduced, letting you customize your gear and have a safe place to store some of your prized equipment. Transmogrification and Void Storage vendors can be found in Cathedral Square, Stormwind, The Drag, and Orgrimmar.
Complete patch notes can be found in the source link.