This section contains information that needs to be cleaned up. Reason: The death knight realm has already been confirmed to be the Shadowlands. Sylvanas committing suicide from ICC in EoN has already been connected to the Shadowlands. Reword still unclear things, move confirmed things to the main section of the page or remove them entirely if they are already incorporated there.
Further, once the new character has completed the starting zone, the player can then choose to level up to 50 in any previous expansion of their choice—vanilla/classic, The Burning Crusade, Wrath of the Lich King, Cataclysm, Mists of Pandaria, Warlords of Draenor, or Legion. The expansion's content will scale perfectly with the character level, and each is tuned so that reaching level 50 involves playing through the content at a similar pace to a similar level of completion as those expansions offered when they were current content.
Let's be clear where I'm coming from, here: I've been playing World of Warcraft almost continuously for 15 years. (I lapsed for a big chunk of the Wrath of the Lich King era for IRL reasons.) While I understand the appeal of WoW Classic, I am very much a proponent of modern WoW; the game has evolved over time to be more accessible for me to play just a couple of hours a week, as real life now dictates. But I tend to play solo or just with one or two friends on a sporadic basis, which means I'm looking for something very different than the hardcore raiding or PvP crowd.
World of Warcraft: Shadowlands marks the eighth major expansion pack for the storied MMO. Judging from a half-hour playing it at BlizzCon this year, it seems like a natural evolution of modern WoW that will run alongside the very-different WoW Classic experience for the foreseeable future. That said, the biggest change wasn't part of my hands-on demo—but don't worry, that won't stop me from geeking out about it in extreme detail.
During the Burning Legion's third invasion, the Knights of the Ebon Blade traveled to the Shadowlands to acquire the Aggregates of Anguish, five tormented essences of powerful souls - Admiral Proudmoore, Soulbinder Nyami, Grand Empress Shek'zeer, Grand Apothecary Putress and Archmage Arugal. Salanaar required these to conjure the Steeds of the Damned for the order's new Horsemen.
But it gets even more interesting when you look at how it will work for alts (second or later characters made by existing players). New characters made by existing players will have the option of leveling up the old way in all the same old zones from the start. But they will also be able to go through the new-player starting experience if that's what players prefer.
A new army of the dead rises: to combat Sylvanas' assault on Icecrown, Bolvar Fordragon— the revered former paladin who took on the mantle of Lich King to keep the Scourge at bay—has raised heroes from among all the peoples of Azeroth to bolster the Death Knights of Acherus. With Shadowlands, pandaren and all allied races will now be able to become death knights.