Lost Soul

There are a number of creatures in Guild Wars that share the name Lost Soul.

In the Realms of the Gods:
 * Lost Soul (Labyrinth), an NPC who gives the initial quest in the Underworld's Labyrinth.

In Prophecies:
 * Lost Soul (Hall of Heroes), NPCs who appear after defeating the end bosses on the Hall of Heroes level of the Ruins of the Tomb of the Primeval Kings.

In Nightfall:
 * Lost Soul (Remains of Sahlahja), the NPC who begins the Remains of Sahlahja Challenge Mission.
 * Lost Soul (Remains of Sahlahja Mission), non-aggressive foes who appear during the Remains of Sahlahja mission.
 * Lost Soul (Gate of Pain), NPCs who must be freed to complete the Gate of Pain mission.