Souls of Lost Undead can be fed to Kingseeker Frampt for 500 souls, which is more than they would give if consumed (200), so it's a good idea to save them up until he is encountered.
Souls of a Lost Undead are commonly found off corpses in the Undead Burg and earlier areas, gradually becoming rarer as the game progresses.
- Northern Undead Asylum
- Found on a corpse in the area after using the Big Pilgrim's Key, on a side ledge before triggering the cut-scene.
- Firelink Shrine
- Up the stairs near Petrus of Thorolund, past the elevator to Undead Parish (may be inoperable) and up a flight of stairs.
- Found on a corpse up the steps near the Giant Crow, along the ledge and at the end of the path.
- Through an archway near the steps that lead to the Giant Crow, the corpse is hidden behind a wall near a ledge overlooking Blighttown.
- Up the path towards Undead Burg. The corpse is hanging on a ledge near an Undead Soldier.
- Past the entrance to the aqueduct that connects to the Undead Burg.
- In the aqueduct passage, guarded by an Undead Rat.
- Undead Burg
- Before the first fog door, it can be reached by dropping down into the narrow area below. It is on a corpse, in a building, hanging out of a balcony.
- In the building after the first fog door, before the Hellkite Dragon is first spotted.
- Beyond the bonfire, on the wooden scaffolding where three Firebomb wielding Hollow Warriors are standing.