As Empire of Islenor took rulership over the matters of Silver Shore Island in 3550, their iron grip had tightened. After banning Faith of Children of The Dancer in 3565, Empire had essentially banned the way of life of Drow of the Mori'tarna.
In a last attempt to find common ground, Empire representatives meet the representatives Great Matron Council of Mori'tarna in a negotiation. Lead by the Mother of Shadows, Drisintralin Shadowblade, the drow come to the surface and meet the Empire diplomats.
Exact record of the events where lost, as the disagreements and suspicions between the two group would end up in to a bloodpath, that started a cold war between the two sides. Drisintralin Shadowblade was killed in the process, causing great stirr in the drow community.
Shynt'vyrae Shadowblade, Drisintralin's daughter takes her place as the Mother of Shadows and soon greatest of the routes to surface from the Mori'tarna are collapsed in purpose to stop Empire invasions. For the next 40 years or so, drows build and collapse their tunnels to surface frequently to keep Islenorians out but to continue connections with rest of the island.