Key of Three Parts
The three pieces of the tripartite key were initially housed in the altar rooms which lay beneath Britannia's great dungeons. Each of the altars within these chambers represented one of the Three Principles, and was fitted with four depressions which were designed to house several of the Stones of Virtue. The Stranger, in their quest toward Avatarhood, would need to collect these stones and install them into the altars they corresponded to, as doing so would allow them to retrieve the three parts of the key. Eventually, after passing through the numerous trials of the Abyss, and were able to this device to access the Codex of Ultimate Wisdom and attain the mantle of the Avatar.
Years later, during the Avatar's imprisonment within the Abyss by Baron Almric, the hero would once more have need of the Key of Three Parts, that they might use it to reenter the dungeon's innermost chamber and thereby prevent the release of the daemon known as the Slasher of Veils. In the time since their last encounter with it, however, the key had again been split into three pieces and scattered throughout the Abyss. The Key of Courage lay within a chamber fraught with terrible beasts. The Key of Truth had been bound to the shrines of the dungeon, such that it could only be retrieved through use of a specific mantra. The Key of Love, for reasons unknown, would only appear when the tears of a bereft lover mixed with the magma of the volcanic dungeon.
Eventually, the Avatar retrieved the three parts of the key and reassembled it once more, and was thereby able to again enter the Chamber of the Codex, wherein they used the eight Abyssal talismans to banish the Slasher of Veils back to the plane from which it had come.