The Great Houses began as various departments within the Imperial Bureaucracy. During the Isolation, they slowly seized control, absorbing other departments, consolidating power; eventually cementing themselves into positions of great authority within the city.

Each of the Great Houses controls a District of Rastaban, renamed in their honour.

Membership of a Great House can be hereditary, if the Head of House approves it.

Whilst many citizens may belong to a Great House in name, far fewer are part of the group that effectively holds power within that House.

Great House Esteban used to be the Department of Taxation.

Now they are Rastaban's largest banking conglomerate.

Esteban headquarters is a large enclave pressed up against the walls of the Imperial Palace.

Great House Telemere used to be the Department of Justice.

Now they control the largest private army in the city, and their District boasts a formidable legal system.

Telemere Headquarters is a small fortress standing alone in a large expanse in their District.

Great House Rom used to be the Department of Extraplanar Affairs,

Now they are a noble house comprised primarily of Plane Weavers.

Their headquarters is built upon the blackened ruins of the Imperial Archive.

Great House Keelen is not a Great House.

The moniker is a joke, but reveals a deeper truth: Keelen wield enough power in Rastaban to rival the official Houses.

Keelen are a collection of criminals, kingpins, and ne'er-do wells.

Keelen provide smuggling, assassination and other services vital to the smooth running of legitimate business.

Their base of operations is almost certainly somewhere in the Barrens, the District they claim as their own.