The themes of frost and undeath pervade "Wrath of the Lich King." "WoW's" first hero class, Death Knights, will become available to players who complete an involved questline. This won't involve changing one of your existing characters' class; instead, you'll unlock the ability to create a new Death Knight on your account that will start at a high level.

Naxxramas, the floating necropolis that was the highest reach of pre-expansion "WoW's" raid content, will be retooled as a 25-man raid for level 80 players. Only a tiny fraction of players were able to experience Naxxramas at level 60, and the designers at Blizzard have publicly opined that it is possibly their best work to date, so this seems like a natural fit.

A new profession, Inscription, will allow players to customize their spells (and sell scrolls to allow others to partake in the goodness) with additional effects. For instance, you could have a Fireball that incorporates a knockback component, or a Prayer of Healing with a reduced mana cost.

Player-vs-player combat isn't being neglected, of course. A new battleground that Blizzard hasn't said anything about yet will be included, and siege weapons and destructible buildings will be incorporated into the world for non-instanced PvP combat.

Sell your soul

Death Knights in "World of Warcraft" will be similar to the fallen champions that led the Scourge in "Warcraft III." Broken shells of their previous selves that have been re-molded into terrifying wielders of the powers of darkness, Death Knights will be available to both Alliance and Horde. The official lore kludge is that they are feared and mistrusted by all, but grudgingly accepted as weapons in the fight against the Scourge because of the powers they bring.

Game mechanic-wise, Death Knights will fill both tanking and damage-dealing roles. Rather than having a mana bar, they will socket runes into their runeblades in various combinations of Frost, Unholy, and Blood. Using skills will cause one or more runes to darken and be unavailable to power further attacks for a certain amount of time. However, the balance of runes that fills your blade is up to you, opening another avenue of character customization.