The Lich King's power is being felt across Azeroth.
Mysterious crates first found in Booty Bay have been turning up in unusual places.
What first started as isolated instances in Stranglethorn Vale has become an epidemic of plague. The likes of which Lordaeron knows all too well.
Just when they were needed most, the Kirin Tor of Dalaran appeared to have removed themselves - a crater the only memory of their passing.
To counter the unforeseeable infection, the Argent Dawn has mounted defense in major cities with healers at hand to cure those who cannot cleanse themselves.
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As a player, I've found the zombies to be a nuisance at best, and server-crashing at worse. A raid of zombies thought it would be a great idea to attack capital cities and the mounted defense of paladins defending the city, much less zombies storming the keep, was quite a strain on the already full server that I play on.
I find it interesting that becoming a zombie, Blizzard has allowed temporary cross-faction communication. As zombies naturally speak zombie, the plague does not distinguish between those who were formerly alliance or formerly horde. Once dead by the merciless disease, you awaken as scourge. Players are able to experience first-hand what befell the citizens of Stratholme.
Also, keep looking for a rumored new boss in Karazhan for this special event. It's not uncommon for Blizzard to introduce new loot for a limited time due to these special events and Kara appears to be the location of this year's - if MMO-Champion is not mistaken.
Being sad is the same as giving up.