Here is the full list of all 12 Lucifer Within Us achievements.
Witness the return of the daemons.
Find all psychological evidence in the Chapel Case.
Find all physical evidence in the Chapel Case.
Find all contradictions and psychological evidence in the Graveyard Case.
Find all physical evidence in the Graveyard Case.
Find all physical evidence in the Two Brothers Case.
Find all contradictions and psychological evidence in the Two Brothers Case.
Ask each suspect about every evidence and testimony statement found in the Two Brothers Case.
Ask each suspect about every evidence and testimony statement found in the Graveyard Case.
Ask each suspect about every evidence and testimony statement found in the Chapel Case.
Obtain all testimonies and evidence in the game.
Purge the Abbey of this infernal herb.