The character is able to advocate for Evil characters before the Good Elder Powers, reducing the Advocate's own Morality to raise the Morality of their patient. Every use of Sin Eater costs 1 AP and 1 Morality and raises the target's Morality by one point. This ability only works on Evil characters with a Morality of -20 or below, and is able to raise them to the point of Neutrality (-19 Morality) after which the patient must do the rest.
This ability will work on Tier 2 demons (Pariahs and Defilers), allowing the Advocate to act as a patron and mentor on the path of Redemption. It will not work on Tier 3 demons, including the Fallen, as they have already made a choice that is irreversible within the duration of a Breath.
Sin Eater is considered a Healing action, but as it is healing of the patient's soul and not their body, it is not limited by status effects that otherwise limit healing such as Blood Curse.