Requires you to get the Umbral ending, which is accessed by various quests given by Molhu. But, to get them, you need to reach the Revelations Depths in the mid game, and defeat a boss called Dervla. You must not cleanse any beacons for the entire game.

Dervla guards a special room, which you need an item that costs 50 Umbral Scourings. Purchase it, and take it to the altar and then use it. This unlocks a room called Mother’s Lull. From there, the Lull will grant you access to quest from Molhu, requiring items from certain NPCS. These NPCs include Damarose, Gerlinda, Iron Wayfarer and Pieta. Simply play through the storyline in order to get the Damarose and Iron Wayfarer storylines going, and rescue Gerlinde from her cage in Pilrim’s Perch. As you progress the storyline by defeating Beacon bosses, you will gradually unlock items and boss battles to use on or against these NPCs when appropriate. You must alos get the Mark of Adry in the Abbey of Hallowed Sisters, but don’t use it on the door to open the Bramis Castle. You do not need to go into Bramis Castle to get the Umbral ending. When all are defeated, and you beat Ellianna towards the end of the game, you’ll be able to get the Umbral Ending.