Sword's Rest is the entry chamber to the Halls of Reflection. From the doorway, Frostmourne can be clearly seen on the altar in the center of the room. After the Lich King appears, he will summon Falric and Marwyn to kill the intruding party. The spectral mobs assisting Falric and Marwyn are heavily based on the Alliance units from Warcraft III, and are most likely the ghosts of the soldiers betrayed by Prince Arthas in his obsession to obtain Frostmourne.