A Healed soul is a new item presented in the Better Save Soul DLC. First, a Harmed soul is acquired by extracting it out of a Corpse with the help of the Soul extractor. Then, the Harmed soul can be turned into a Healed soul with the help of a Soul healer, creating Sin shards depending on the number of bodyparts used in the Soul's cleansing.
Each Sin Shard stored in a Soul Container passively increases the maximum Soul Gratitude you can store by one.
Any Healed soul left outside a Soul container will deteriorate slowly, eventually turning into a Sin shard. In turn, Harmed souls will deteriorate much faster.