Cloven Crystal

The Cloven Crystals are the three magical keys to the seals binding Uk'otoa beneath the Lucidian Ocean. They resemble an amber eye with a vertical slit pupil, like a cat's or snake's eye. Uk'otoa urges his warlocks to seek them out and place them in three temples located throughout the Menagerie Coast so that he may be eventually released. Those who use a Cloven Crystal to unlock one of the seals are rewarded by Uko'ota with control over water; mechanically, the character gains the ability to cast Control Water once per day.

Description
The Cloven Crystals are polished stones that are amber-yellowish color with striations that refract light around them. On one side, there is a pointed oval line carved in about three inches across. They are cold to the touch. If a warlock bound to Uk'otoa touches a crytal, it is immediately magically absorbed into their body.

History
There are three Cloven Crystals, each sought by the warlocks and servants of Uk'otoa so that he may be freed from his prison under the seabed of the Lucidian Ocean and again take his place as its ruler. To release Uk'otoa, the Cloven Crystals must be placed into matching pits inside three temples located on Urukayxl, at the Gravid Archipelago, and in a forest north of Nicodranas, likely the Cyrios End Forest. These temples were originally dedicated to Uk'otoa, but they were infiltrated by followers of Zehir at Zehir's command and used to seal him.

In 835 PD and the years preceding, ownership of these crystals was most notably passed between the warlocks Fjord, Avantika, and Vandran:

Labenda Swamp crystal
While investigating the subterranean tunnels of the Labenda Swamp in, the Mighty Nein found a Cloven Crystal resting in a pool of seawater, unusual as all other water in the tunnels were fresh. Before Caleb Widogast could finish casting Identify, Fjord touched it. He immediately entered a dreamlike trance and had a vision of Vandran standing over a body, thrusting a Cloven Crystal into his chest, and summoning the Sword of Fathoms to his hand. While having this vision, Fjord also thrust the Cloven Crystal into his chest, magically absorbing it. Afterward, the Sword of Fathoms had a representation of a Cloven Crystal in its crossguard.

In, Fjord discovered that Avantika hired Ionos Jagentoth to search for this Cloven Crystal, falsely describing it as a family heirloom, and instructed him to deliver it to Marius LePual in Nicodranas before the end of Quen'pillar. Ionos then subcontracted the Iron Shepherds to locate it. Her letter to Ionos, with which she included a drawing of the Cloven Crystal, spurred Fjord to travel to Nicodranas to seek information about his Cloven Crystal and Uk'otoa.

After Fjord eventually destroyed the Sword of Fathoms at the Cinderrest Sanctum in, he incorrectly believed this Cloven Crystal destroyed as well. It remained inside him, as the representation on the Sword of Fathoms was merely symbolic, and the Wildmother referred to it as a "seed of darkness" that she could not heal. Months later, in, he was attacked by three warlock deep scion and a group of sea spawn sent by Uk'otoa to retrieve the crystal; though Fjord was killed, Uk'otoa's servants fail to escape with Fjord's body and were killed. Fjord was brought back to life in, and the crystal was separated from him through Greater Restoration. The process caused him to painfully vomit gallons of seawater until the crystal left his body. It was then placed inside Caleb's Vault of Amber for safekeeping.

The Cloven Crystal was again located by Uk'otoa's servants, this time accompanied by an undead Avantika, while the Nein were traveling aboard the Midnight Hammer through the Frigid Depths in. A deep scion dispelled the Vault of Amber spell, exposing the crystal, and Avantika successfully stole it in  and fled into the sea. After a quick pursuit, Fjord killed her, retrieved the Cloven Crystal, and placed it in his Bag of Holding.

The Bag of Holding, and thus the crystal, was stolen by the Tombtakers in. Lucien, the leader of the Tombtakers, proved he knew he had possession of the crystal by taunting Fjord with it in. After Lucien's death in, Fjord regained possession of the Bag of Holding, which still contained the Cloven Crystal.

Fjord continued to carry the Cloven Crystal with him aboard the Nein Heroez. In late 836 PD, he considered giving it to the Cobalt Soul for safekeeping after he and Jester Lavorre thoroughly investigate the exact location of the third and final temple north of Nicodranas. Upon being reminded that the Nein Heroez was repeatedly attacked at sea by agents of Uk'otoa in search of the crystal, he indicated accelerating plans. However, out-of-character, Travis expressed uncertainty about his ultimate plans for it.

Avantika's crystal
Many years before 835 PD, a pirate of the Revelry had a Cloven Crystal. Vandran and Avantika fell into a dispute with this person and they killed them, arranging it to appear as an accident. Vandran took the crystal, which he presumably absorbed. Between himself and Avantika, this was the only crystal they possessed during their work together to release Uk'otoa.

Growing doubtful of Uk'otoa, Vandran abandoned the quest to free him and fled to Port Damali. There, he was apparently able to remove it from himself. He had the crystal sold at auction in the city and used the money to buy the Tide's Breath. Avantika discovered that it had been sold, and she stalked the collector who bought it to an unknown island and killed him. She then absorbed the crystal, causing an eye resembling the Cloven Crystal or Uk'otoa eye to appear in her right palm. Apparently, she did not realize that Vandran was the one who put this Cloven Crystal up for auction, as she told Fjord that she believed Vandran would not part with it; she believed Vandran's crystal to be either the one Fjord possessed or one possibly aboard the Tide's Breath.

Avantika eventually left it at the temple on Urukayxl in, receiving in return the ability to cast Control Water once per day.

Tide's Breath crystal
Vandran kept a Cloven Crystal in a metal box aboard the Tide's Breath, hidden underneath a bookcase in his quarters. It was apparently acquired after he forsook Uk'otoa, as the crystal he originally carried was sold at auction to buy the Tide's Breath and ultimately owned by Avantika. When the Tide's Breath sank into the Diver's Grave in early 835 PD, the crystal was taken with it to the bottom of the sea.

In Avantika expressed her belief that that Vandran would not part with the crystal he originally carried, so she sought to find the wreckage of the Tide's Breath to locate the final unaccounted for Cloven Crystal. After her death, Fjord visited the Diver's Grave in search of it in, only to find that it had been taken from the wreckage. It was tracked to Dashilla's lair, where Fjord absorbed it. Afterward, the Sword of Fathoms had a symbolic representation of a Cloven Crystal in its pommel.

Shortly after, in, he left it at the underwater temple at the Gravid Archipelago, receiving in return the ability to cast Control Water once per day and a vision of the third and final temple's location. This caused the representation of a Cloven Crystal in the Sword of Fathom's pommel to disappear.

Trivia

 * The Cloven Crystals, Uk'otoa's eyes, and Fjord's eyes closely resemble one another.
 * Avantika and a deep scion warlock of Uk'otoa bore tattoos resembling Cloven Crystals on their chests.