Blizzard has now added the introduction quests to the Nazjatar zone for each faction, which is the questline leading to the new raid of Rise of Azshara. Completing these quests unlocks the Nazjatar zone, the remainder of the Nazjatar Quests and the Bodyguard system.
Story spoilers in this post! Do not continue on if you don’t want to be spoiled.
Both of the intro questlines are very similar.