As guardian of the Well of Wonders, Nyx's waters have the ability of restoring health to people, but is only permitted for those who are not yet destined to die. In Agrabah, she meets three brothers, Taj, Rafi and Cyrus, who desperately want to acquire some of the water to heal their mother, Amara. Though Nyx can indeed detect that Amara is suffering from fatal burns, she refuses to give them the water as it is their mother's fate to pass on rather than survive. Cyrus insists on arguing against this, since Amara is injured due to his own mistake, and he wants to right a wrong. Nyx sticks to her prior judgment, warning them to return the water or pay the price, before disappearing under the surface of the well's water. The brothers leave with the water, and she later materializes in their home to deal out a punishment for their theft. Amara attempts to plead on her sons' behalves, but Nyx is angered that the three chose to let desire cloud destiny. She entraps the brothers into three bottles, transforming them into genies, and cursing the trio to spend their lives serving the desires of other people. Afterwards, Nyx scatters the bottles across Agrabah. ("Dirty Little Secrets")
Accessed through a door in Wonderland, Nyx is visited by a now human Cyrus at the Well of Wonders. Cyrus begs her to have mercy on his brothers, Taj and Rafi, who she cursed to become genies after they took water from the well because he asked them to. She states that only when the water is returned will the curse be lifted. Cyrus believes returning the water to be impossible since he gave it to his mother over a hundred years ago, but Nyx can sense that she is still alive. When he questions her about his mother's whereabouts, she doesn't respond and only sinks away to below the well's surface. ("Dirty Little Secrets")
Later, Cyrus returns to the Well of Wonders along with his mother, Amara. Nyx surfaces as Amara attempts to sacrifice herself to break the spell on her sons. Jafar attempts to put a stop to it by killing Amara and turning her body into water. To this, Nyx disappears into the well to avoid danger. Jafar moves to get rid of Cyrus, when suddenly Alice appears out of the White Rabbit's portal. An altercation ensues, with Jafar freezing Alice in place, as she shouts for Cyrus to return the water in Amara's body to the well. Cyrus almost succeeds, nearly fulfilling his debt to Nyx, until Jafar magically grabs the ball of water before it can reach the surface of the well and bursts it. Alice then reveals to Jafar that he didn't steal the water from them, but had in fact stolen the returned water from Nyx. Enraged at his thievery, Nyx rises out of the well as Jafar, completely caught off guard, turns around to face her. She serves out the same punishment given to those who steal her water by enslaving him as a genie. In doing so, the laws of magic which Jafar broke are restored and Cyrus' brothers are freed. Nyx senses a deceased woman who Jafar once killed, but knows this particular person's time is not up yet, so she gifts Alice and Cyrus a canteen of the well water to revive her. ("And They Lived...")
- Teleportation - Ability to magically teleport oneself and/or others from one location to another.
- The name "Nyx" is of Ancient Greek origin that means "night".
- Nyx's grisly, murky skin is based on what happens when a dead body is floating in water less than 70 degrees Fahrenheit (21 degrees Celsius) for a period of time (about three weeks), which causes the skin to turn greenish black. This is fitting, as Nyx lives underwater. ("Dirty Little Secrets", "And They Lived...")
|Once Upon a Time in Wonderland|
|"Down the Rabbit Hole":||"Trust Me":||"Forget Me Not":||"The Serpent":||"Heart of Stone":||"Who's Alice":||"Bad Blood":|
|"Home":||"Nothing to Fear":||"Dirty Little Secrets":||"Heart of the Matter":||"To Catch a Thief":||"And They Lived...":|
|Once Upon a Time: Season Six|
|"The Savior":||"A Bitter Draught":||"The Other Shoe":||"Strange Case":||"Street Rats":||"Dark Waters":||"Heartless":||"I'll Be Your Mirror":||"Changelings":||"Wish You Were Here":||"Tougher Than the Rest":|
|"Murder Most Foul":||"Ill-Boding Patterns":||"Page 23":||"A Wondrous Place":||"Mother's Little Helper":||"Awake":||"Where Bluebirds Fly":||"The Black Fairy":||"The Song in Your Heart":||"The Final Battle Part 1":||"The Final Battle Part 2":|
- Nyx. Behind the Name. Retrieved on November 25, 2018.
- Borrell, Brendan (June 10, 2009). How long do dead bodies remain intact in the ocean?. Scientific American. “And if the body is floating in water less than 70 degrees Fahrenheit (21 degrees Celsius) for about three weeks, the tissues turn into a soapy fatty acid known as "grave wax" that halts bacterial growth. The skin, however, will still blister and turn greenish black.”