The Widow Harun
Raumathar was a vast empire which controlled The Endless Waste and surrounding areas millennia ago, dominating and influencing the northern half of the campaign area in much the same way that ancient Imaskar has influenced the southern area. The legacy of Raumathar is a number of prominent ruins, some of them well known adventure sites such as Winterkeep, as well as many lesser known sites and magical effects scattered across the land. Unlike Imaskar, the people of Raumathar did not vanish from the land. The Raumvira ethnic group of Almorel and its surrounding region are modern-day descendants of the folk of Raumathar.
Raumathar is described in much more detail in the Forgotten Realms core books and supplements. Please consult these if you wish to learn more.