The Seven cities of the Blood elves, located on the shores of the Hieyokscream sea, were some of the most important ports of the demon-held Polforia, being an important trade hub.
The highly stylized, tall and seemingly light buildings of the Daiman'Yar blood elven architecture will become characteristic of the seven cities.
During the High Elf imperialism of the Late Elfic Age, while the High Elves did not officialy found kingdoms or realms in Polforia, they set in the northern coastal shores of it trading posts, as a vanguard for maybe further expansion: However, the catastrophes related to the arrival of humanity cut these projects short, and the polforian high elves' ventures were abandoned. Local Rossnes elves, who had traded with the High Elves however did continue the settlements.
During the Age of Invasions, as Polforia was largely overrun by Orcs first, then Kanovs and Humans, many Rossnes light elves migrated northwards, settling along the Hieyokscream shores, often around these small trading outposts that began to raise into small cities and petty kingdoms:
However they too will be menaced by Kanovs and Humans, and many were conquered.
When the Dark Legion of Demons arrived to Polforia, the elves of the northern provinces, last remnants of the Polforian Rossnes elves, often greeted them as liberators, joining the Confederation of Free Peoples.
Under the unified demonic Polforia, under the Pax Daemoni, the now blood elven cities will prosper under demonic rule, as Seven city states arose.
However, while successful due to trade and with a more and more refined culture, there began the feeling amongst some Blood elven elites that they were being held back by the Dark Legion and their heavy taxes.
That's why at first during the First War of the Power, they received the High Elves as liberators... but soon they proved themselves to be only new tyrants.