The Arathi settlement in Hallowfall is only fifteen years old. They originally came from a new place we haven't seen before, will we visit this zone in the future?
In The War Within, Hallowfall is home to the Arathi — descendants from the first human empire of Arathor. However, while Arathor was based in the Eastern Kingdoms, these Arathi are part of a group that splintered from the original empire and built their own Arathi Empire across the sea.
Hallowfall is not this empire — the city that the Arathi have built here is called Mereldar — but early on Faerin Lothar, presumably a distant relative to Anduin Lothar and a major character in the War Within, explains why we find Arathi in this zone.
Around fifteen years ago, an expedition was sent out from the Arathi Empire, to follow their Emperor's vision of a holy light. Their armada was caught in a terrible storm, but a golden radiance enveloped them and transformed them down to Hallowfall. They have been marooned in the zone ever since. They have named the light that guided them, the crystal «star» that lights up the zone, Beledar — or the «Emperor's Vision».