Circa 1491 DR, Nezznar sent Vyerith as a messenger to convene with King Grol of the Cragmaw tribe. The goblinoid king had recently captured Gundren Rockseeker, an ambitious dwarf who believed he had found the location of the Lost Mine of Phandelver.
Vyerith arrived at Cragmaw Castle to request the dwarf and his map to the lost mine. However, Grol did not wish to hand them over, without being given anything in exchange. The doppelganger wanted to first speak with Gundren to find out if anybody else knew of the location of the lost mine, and then kill him. Vyerith was in no way loyal to Grol, and planned to escape if he was slain. However, if cornered, the doppelganger would fight to the death, preferring that fate over being captured.