Daila's Secret Quest

Daila's Secret Quest is available on Ultimate difficulty only. Although not technically a quest, as no quest log objectives or rewards are given to the player, it expands upon the lore relating to Daila Thornsbury and her brother Dravis, and unlocks the secret Edge of Reality level.

Guide
To complete the quest, the player must find several items. Each can only be found after acquiring the one before. 1). The Legendary Dagger Stormheart, located within a breakable urn inside the Tomb of Korvaak. 2). Dravis' Letter to Daila - First Entry. Following the hint given in the Excerpt from Daila's Diary note, the player must find the Weeping Oak, a large tree full of hanged corpses located in The Blood Grove. At the base of the tree is a small plume of blue smoke; moving close enough will add the quest item to the inventory, and the following text will appear on-screen:
 * You feel a chilling breeze, but there is no wind...
 * The note text provides a clue to the location of the Second Entry.

3). Dravis' Letter to Daila - Second Entry is found in Anguish, the fifth level of the Steps of Torment, in a secret room in the south corner. A pile of skulls with a plume of blue smoke can be seen inside; moving close enough will add the quest item to the inventory, and the following text will appear on-screen:
 * A sense of dread overwhelms you...
 * The note text provides a clue to the location of the Third Entry.

4). Dravis' Letter to Daila - Third Entry is found in The Forsaken Wastes, inside a ruined house to the north of the area. A small plume of blue smoke can be seen inside; moving close enough will add the quest item to the inventory, and the following text will appear on-screen:
 * This place feels strange...
 * The note text provides a clue to finding the Final Entry.

With all four of the above items in the player's inventory, a Bound Spirit will spawn in the hidden area of the Gates of Necropolis located to the northeast from the riftgate, beyond some Aether Crystals and a wagon.

Giving the Bound Spirit a Salt Bag amulet will cause a Chthonic Rift to open, leading to the Sanctum of the Immortal. There the player will find Dravis' Letter to Daila - Final Entry, and can activate a Loose Torch which opens a Chthonic Rift to the Edge of Reality.