Blizzard is setting the stage for a new invasion of Azeroth, leading to the release of World of Warcraft: Legion on August 30.

A massive pre-expansion patch is scheduled to be deployed tomorrow during maintenance. The patch will bring in some advance content in anticipation of the Burning Legion returning to Azeroth, and a new class of Demon Hunters being unleashed to combat them. Blizzard said that invasions will begin, turning once peaceful areas into battlegrounds, and new quests and activities will open at the Broken Shore, which is the heart of the demonic incursion. More content will gradually be rolled out leading to the full release of the expansion.

Also, for those that pre-ordered Legion, the Demon Hunter will be available for early access beginning no later than August 17. Players will start at level 98, and begin questing in the new starting area of Mardum. The area is set around the time of the Burning Crusade when players were hunting Illidan at the Black Temple.

The patch will bring plenty of class updates as well, so if you haven;t played in awhile, you may want to go in an read up on what changes are happening to your favorite classes.

The 6.3 GB patch has already started to download in the background for existing World of Warcraft players. No word on how long the servers will be down, but patches of this magnitude usually have a few hiccups, so a downtime of at least 12 hours is likely.

In the meantime, check out the teaser new animated feature Blizzard will unveil for the x-pack at the San Diego ComicCon this week.