Sildar Hallwinter is a retired soldier and sellsword who hails from the city of Neverwinter. He is a loyal member of the Lords' Alliance, a political organization that unites the various free cities and towns of the North. In his younger days, Sildar was a soldier who earned himself a place of honor among the Griffon Cavalry of Waterdeep.
He set off to Phandalin from Neverwinter to escort Gundren Rockseeker, who had recently rediscovered the Wave Echo Cave. Sildar had his own reasons for visiting Phandalin, and wished to find out what was happening with his fellow agent of the Lord's Alliance, Iarno Albrek. He also wanted to help Gundren and his brothers re-open the mine, as well as establish Phandalin as a place of prosperity, as it once was.