- Five are given to the player after letting Yoel of Londor draw out their true strength, granting a free level each time. The player must die at least two times after each session before Yoel offers another level.
- Three are granted during Yuria of Londor's questline, once the player completes their wedding vows with Anri of Astora.
- Increases the player's Hollowing level by the number of accumulated Sigils upon death.
- Grants bonus Luck when wielding Hollow-infused weapons if Hollowing is 15 or greater, based on the upgrade level of the weapon.
- Once eight Dark Sigils are acquired, the Lord of Hollows ending may be unlocked.
The Dark Sigil can only be healed by giving a Fire Keeper Soul to the Fire Keeper. The cost of healing is equal to the cost of leveling up a number of times equal to however many Dark Sigils have been accumulated. Once healed, all Sigils will be removed from the player's inventory and Hollowing will be reversed.
Yoel of Londor will no longer speak to the player if healed prior to his death. Should they be healed after, Yuria will become hostile upon speaking to her.
As the Dark Sigil is a key item, proceeding to the next New Game cycle will remove them from the player's inventory, but will retain Hollowing.