The Davy’s Key open Davy Jones’s Locker dungeon.
Davy Jones’s Locker is a medium-high dungeon that is a source of Potions of Wisdom, Potions of Attack, and the Ghostly Trickster UT set.
This dungeon is meant for high level players (Suggested level: 20 and Defense Maxed), because the boss has high damage piercing bullets that inflict the bleeding status effect.
Entrances to the Davy Jones’s Locker can be dropped from the Ghost Ship, an event boss that spawns a maximum of once per realm.
Despite being underwater (according to the Realm Eye lore below), players do not have limited oxygen in this area and cannot die by suffocation, unlike in other underwater areas such as the Ocean Trench and Cnidarian Reef.