EDIT (8:45AM PST, June 16): Horde NPCs that show up during the questline have been added!
SPOILER WARNING! This post contains information that will be released during Patch 8.0, aka the Battle for Azeroth pre-patch. Continue at your own discretion.
To learn more about what will be added (or removed) to the game on the 8.0 Pre Patch, check out our Patch 8.0 Feature Preview guide!