According to eye witnesses, a big fuckoff black dragon rose from the crypts of Neverwinter with a rider addressing himself as Galdeth. They slew many people including most of the army and forced Lord Neverember into the dungeons as Galdeth forcibly took over. From here, he began to raise his army of dragons and militarise the scattered Dragon Cultists that laid underground.
From here, he led a campaign against the Sword Coast, wiping out resistances and taking charge from his seat of power, the Jewel of the North, Neverwinter.

30 years after his return, he has claimed all of The Sword Coast and rumours state he is aiming to expand into Amn (south), Cormyr (east), and the Moonshae Isles (west).