The expansion is set immediately after the events of Legion. Two continents have been added within the Great Sea between the Eastern Kingdoms and Kalimdor: Kul Tiras, one of the major human kingdoms, and Zandalar, the homeland of Azeroth's trolls. While the Alliance and Horde will initially travel to one continent respectively, both continents will be available to both factions at level 120.
The Heart of Azeroth is an artifact given to the player character from the world soul via Magni Bronzebeard. It is a necklace that can use the power of Azerite, the lifeblood of the embryonic titan Azeroth (See Plot, below). Azerite is similar in function to Legion's artifact power, in that it is gathered normally from playing the game and is used to upgrade an artifact; likewise, the Heart is similar in function to Legion's artifact weapons by having the capacity to be constantly upgraded. Unlike artifact weapons, however, the Heart is shared with all of the player's specializations and can empower all eligible pieces worn simultaneously.
Still, it’s terrible to see the new expansion fail so spectacularly at iterating on Legion’s success. It’s hard to believe the two expansions came from the same company. Legion made you feel powerful and unique. Battle for Azeroth grinds at you by taking away as much as it gives. Sure, you can have a shiny toy. Sometimes. If you don’t get too carried away.
As the battle for Darkshore begins, both the Alliance and Horde are blindsided by a new development: High Overlord Saurfang, who had been defeated and captured in the Battle of Lordearon, has suddenly escaped Alliance captivity and is on the run. Sylvanas sends Horde Champions to track Saurfang down, ostensibly to extract him. However, it quickly becomes apparent that the search party is in fact an assassination squad, as Sylvanas suspects Saurfang of colluding with the Alliance in an attempt to dethrone her. While some Horde champions choose to side with Saurfang and help him escape the assassins, other champions remain loyal to Sylvanas and report Saurfang's and the dissenting champions' treachery to her.
That lack of storytelling agency may soon change with Patch 8.1, Tides of Vengeance, which is coming to Battle for Azeroth soon. While there are plenty of fun gameplay changes that should make the expansion better, one of the most interesting additions is that of choice. In an upcoming quest, players will be able to choose whether they want to support Saurfang or Sylvanas — essentially honor or evil — in the struggle for Horde warchief.