The Cloven Crystals are three magical items that resemble an amber cat's eye. The Crystals are critical to releasing Uk'otoa, acting as keys to its confinement. It rewards those who use Crystals to free it with control over water.
The Cloven Crystal has an amber-yellowish color. It has striations that refract light around it. At one end, there is a pointed oval line carved in about three inches across. With all three crystals deposited, Uk'otoa can be released to rule the Lucidian Ocean once again, just as it had done in ages past.
- Inside Caleb's Vault of Amber. This crystal was carried in Fjord's chest until a Greater Restoration removed it.
- Temple of Uk'otoa on Urukayxl (placed by Avantika)
- Underwater temple in Gravid Archipelago (placed by Fjord)
According to Avantika, Vandran already had a Cloven Crystal when she met him. Avantika and Vandran discovered another Cloven Crystal was being auctioned off in Port Damali. They stalked the collector who bought it to an unknown island and killed him. Avantika absorbed the crystal, causing Uk'otoa's eye to appear in her palm.
When Vandran abandoned the quest to release Uk'otoa, he took one Cloven Crystal with him. If Fjord's vision of Vandran absorbing the crystal was accurate, it means Vandran found a way to get the crystal out of his body. He kept it in a hidden compartment in the captain's quarters of the Tide's Breath. Avantika failed to find him or his crystal. She hired the Jagentoth Family from Shadycreek Run to find a crystal and deliver it to Nicodranas.
"Lost Treasures" (2x22)
In the subterranean tunnels of the Labenda Swamp, the Mighty Nein found a Cloven Crystal resting in a pool of water. Fjord touched it and immediately entered a dreamlike trance, during which he saw a vision of his mentor, Vandran, standing over a body, thrusting the Crystal into his chest, and summoning the same falchion that Fjord wielded. Fjord also thrust the Cloven Crystal into his chest. After this incident, the falchion appeared to have a Cloven Crystal resting within it.
"The Journey Home" (2x30)
After killing Lorenzo and the Iron Shepherds, the Mighty Nein searched the house for evidence against the Jagentoth Family, who employs the Iron Shepherds. When they turned Lorenzo's Bag of Holding inside out, they found a letter from Avantika.
"Dangerous Liaisons" (2x37)
"Dubious Pursuits" (2x40)
Captain Avantika deposited her Cloven Crystal in the Temple of the False Serpent on Urukayxl and is rewarded by Uk'otoa with the power to control water. After escaping the temple, Avantika and Fjord met her quarters. She told him about having known Vandran and that Vandran had the Sword of Fathoms. Avantika saw through Fjord's attempt to lie that he did not know Vandran. She seemed to already know that Vandran was dead, but did not know the location of the shipwreck. She convinced Fjord to show it to her on a map. Avantika said the Cloven Crystal was likely there because Vandran would have kept it with him at all times.
"The Diver's Grave" (2x44)
After failing to find the third Cloven Crystal in the wreckage of the Tide's Breath whilst exploring the Diver's Grave, Fjord later discovered and absorbed the Cloven Crystal within the lair of Dashilla. His falchion now had two eyes, one in the hilt and one in the pommel.
"The Second Seal" (2x47)
After the Mighty Nein defeat the deep scion and chuul guarding the ruined temple located underwater at the Gravid Archipelago, Fjord deposits one of his Cloven Crystals at the location and is rewarded with the power to control water. Uk'otoa also gifts Fjord a vision of the third and final temple's location. 
"Clay and Dust" (2x72)
"Dark Waters" (2x98)
Uk'otoa sends three warlock deep scions and a crew of sea spawn to retrieve the remaining cloven crystal from Fjord's body, revealing that the crystal in the Sword of Fathoms was only symbolic of the crystal still within Fjord.
"High Seas, High Stakes" (2x99)
After the attack on the Ball-Eater while sailing near Urukayxl on the way to the peace talks, a Greater Restoration spell allowed Fjord to vomit out the remaining crystal, and it was placed in Caleb's Vault of Amber for safekeeping.
- According to Avantika, Vandran already had a Cloven Crystal when she met him. This seems to confirm the accuracy of Fjord's vision of Vandran absorbing a Cloven Crystal after killing its previous owner.
- ↑ See "Lost Treasures" (2x22) at 2:47:39.
- ↑ See "High Seas, High Stakes" (2x99) from 0:58:54 through 1:00:35.
- ↑ See "Dark Waters" (2x98) from 5:00:04 through 5:00:24. Matt confirms that the Cloven Crystal in the Sword of Fathoms was symbolic of the crystal which remained within Fjord's body.
- ↑ See "Dubious Pursuits" (2x40) at 43:39.
- ↑ See "The Second Seal" (2x47).
- ↑ See "Dubious Pursuits" (2x40) from 2:43:23 through 2:44:31.
- ↑ See "A Hole In the Plan" (2x42) from 3:08:55 through 3:09:24. Avantika's journal details the circumstances of Vandran leaving the path of Uk'otoa.
- ↑ See "The Diver's Grave" (2x44) at 37:01. Jester finds a box that used to hold a Cloven Crystal
- ↑ See "The Journey Home" (2x30) at 50:58. The Mighty Nein find Avantika's instructions for delivering the crystal in a house owned by the Jagentoth family
- ↑ See "Lost Treasures" (2x22) from 2:57:01 through 2:59:49. Fjord has a vision of Vandran absorbing a Cloven Crystal and simultaneously absorbs the Cloven Crystal found in the Gentleman's safe house
- ↑ See "The Journey Home" (2x30) at 51:12.
- ↑ See "Dangerous Liaisons" (2x37) at 2:14:34.
- ↑ See "Dubious Pursuits" (2x40) from 2:41:01 through 2:49:56. Fjord and Avantika's talk in her cabin
- ↑ See "The Diver's Grave" (2x44) from 3:34:52 through Fjord absorbs the Cloven Crystal found in Dashilla's lair.