The Underdark Pact

During the great war the more intelligent and powerful races inhabiting the Underdark formed an alliance in an attempt to overthrow the overworld. The alliance was made of the three primary dark races, the Drow, the Duergar, and the Illithid. In a particularly difficult battle, both the Drow and Illithid agreed to leave the Duergar to be crushed by the forces of the overworld while they retreated to their capital cities. Shortly after, both cities where struck by a Voidbringer staff.
In order to survive in the new aether, the Illithid and the Drow combined their two capital cities into one, using their combined power to form a permanent penumbra of darkness around it.
While their combined power is unmatched by any other individual faction, the continuous political (and occasionally litteral) backstabbing among the different internal houses has prevented them from making any concerted efforts towards domination.

Structure

There are many different Drow and Illithid houses, each battling for power within the pact

Alternative Names

The Pact, the Divided Houses