Urthin-Mejin is an Underdark empire spread across Brucrumus's Tier 1 and Tier 2 Underdarks. In the upper level tier, Xalyth, Urthin-Mejin's lands cover much of the same area as the surface empire Angrod. Both of these elven nations, one predominately wood elf and the other drow, have been at odds for five centuries. Their conflict started shortly after Eldalweril fell in the High Down War (1285-1304). A decade after the war's end, Urthin-Mejin moved in and started staking claim to Eldalweril's adamantine mines and other natural resources. They then went on to capture the city-state Jhaldrym. Back on the surface, the Angrods saw this land grab and new empire in the area as nothing more than a name change, yet the same enemy; with an Andgrod view that all drow of Menortamon are staunch followers of Lolth with hardliner beliefs. There is truth in this view with one of the tenets of Urthin-Mejin's major church to Lloth, the Temple of the Fifth Strand, says that drow are duty bound to fight surface elves on contact.
In the past, Urthin-Mejin has allied with the dragon cult Vith Alok and with the city-state Rumaktharga.