Abyssal Depths are an underground dungeon sometimes found when completing the final Abyss in the area.

The Abyssal Depths contains many Abyssal monsters and all Rare monsters will have an Abyssal Modifier.
At the end of the Abyssal Depths is a more powerful Rare with both a Lichborn Modifier and an Abyssal Modifier. Defeating this Rare will unlock valuable chests nearby.

The chests at the end of the Abyssal Depths can also drop pieces of Preserved Bone, but also can rarely drop additional exclusive Omens and Lineage Supports.

At higher levels the Abyssal Depths can lead to powerful Boss Fights.