Calypso was a sea goddess and the lover of Davy Jones. Calypso was as harsh and untamable as the sea itself, but nevertheless fell deeply in love with Davy Jones. She asked him to carry out the duty of ferrying souls drowned at sea to the afterlife, giving him use of the Flying Dutchman to visit the dimension between worlds that came to be known as Davy Jones' Locker. As a reward for carrying out a decade of service, Davy would be reunited with Calypso for a single day, and if she was faithful, he could come and go on land or sea forevermore afterward.
Davy remained true to his word, and spent the next ten years faithfully carrying out his duty. Calypso did not wait for him when he returned to the land of the living, however, as her very nature would not allow her to wait. Heartbroken and enraged, a vengeful Davy Jones made a deal with the first Brethren Court to imprison Calypso in human form. Led by the original Pirate King, the Pirate Lords' nine pieces of eight were used to bind Calypso into the body of Tia Dalma, and only with all nine pieces could she ever be released. With Caylpso's fiery and unpredictable nature bond, the Brethren Court deemed the seas safe to travel as they so pleased.
Afterwards, Dave Jones returned to the world of the living and left the dead to wander aimlessly in the Locker. However, Davy's grief at Caylpso's abandonment of him, and guilt at the part he played in her imprisonment became so great that he carved out his own heart and locked it in the Dead Man's Chest. For abandoning his duty, Davy was slowly transformed into an amalgamation of human and tentacled sea creature to reflect the man inside, and his crew suffered similar disfigurements.
Tia Dalma's personality is flirty and playful (according to the legend, Calypso was something of a seductress), and she enjoys speaking in riddles. She speaks with a thick West Indian accent, and all her "th"s come out as "d"s. Her language is Jamaican Patois, so she often uses grammatically strange phrases, such as "him carve out him heart."
When Jack Sparrow has a need to travel "up river" to figure a means of weaseling out of his debt to Davy Jones, he and his crew travel to Tia Dalma's shack deep in a swamp. She notices Will has a "touch of destiny" about him and takes Jack the Monkey as payment. She gives Jack a Jar of Dirt, deeming that carrying land with him will help keep him safe from Jones and using her crab claw means of prediction, charts a course to find the Flying Dutchman. At the end of the film, she tells the crew there is a way to free Jack from Davy Jones' Locker and reveals that she has brought Barbossa back to life to assist them.
Tia travels with the crew on their journey to find a means of getting to the Land of the Dead. First going to Shanghai, they retrieve the Navigational Charts and make a deal with Sao Feng for a ship and additional crew. When making their way off World's End and down into the Locker, Tia sends a band of crabs to retrieve Jack and the Black Pearl, which they use to find their way out.
When the Pieces of Eight are burned, Tia grows into Calypso. Despite her anger towards the Brethren Court for having imprisoned her in the human shell, Calypso's bitterness over Davy's rejection was greater, and she agreed to help them defeat him when they performed the ritual to release her. When Barbossa asks her to "unleash his fury upon those who dared pretend themselves her master or his," she shouts in French "Across all the seas, find the path to he who wrongfully entombed me!" and then disintegrates into a swarm of crabs that scuttle overboard. Free at last, Calypso vents her fury as as powerful storm, bringing about the Battle of the Maelstrom. After Davy Jones' death, Calypso's fury is spent and the sky and seas become calm again.
Tia makes several appearances in this book series about Jack's youth.
By Jack's sixteenth year, Tia was already established on the Pantano River, and was considered to be the greatest mystic in the Caribbean. She returned to Jack the eye of Stone-Eyed Sam along with two beads that allowed him to summon the spirit of Montecuhzoma to defeat the phantom Hernán Cortés. Later, during a meeting with the crew of the Barnacle, Tia professed to have divined something of Sparrow's future, and seemed to be aware that the Chest of Cortés would play a part in his later life. It was during this time that Tia provided Jack with catnip; the means to return Constance Magliore to her human form, after Tia herself transformed the girl into a cat.
Tia appears in the series. She is a member of the Overtakers, despite her status as a neutral character, although she is shown to barely get along with her comrades. However, she holds Maleficent, a fellow practitioner of the black arts, to the highest regard; she also speaks politely to Jafar. Tia first appears in the fifth book, Shell Game, at Castaway Cove in a cabana. The Overtakers, who boarded the Disney Dream, had brainwashed sailors try to bring her back to the ship, but Tia refused, demanding a liaison from the Overtakers to meet her instead. Jafar was sent to talk her into boarding the ship, which proved successful; she knew that Maleficent never broke a promise, which in this case was to gift the lamp to Jafar for his services. She then cast a spell on half of the brainwashed sailors, for some unknown reason; Maleficent then appeared as a distraction to allow Tia the luxury of leaving while Finn was kept busy. The Overtakers placed her in the power generator, where they kept their DHI server; basically, she was serving as the server's watch dog. or gatekeeper if you prefer.
Finn and Willa infiltrated the room, prompting Tia to attack her voodoo magic. Finn got the flash drive from the server, rendering it useless; Willa tried tying up Tia using her own necklaces. However, Finn caused a power outage, allowing her to capture Willa. However, the power surge had done something to Finn; he usually didn't think about killing a Disney villain because it was against Disney to do so, but her grabbed Tia by her throat, demanding the release of his mother from Maleficent's control, or he would snap her neck. Unable to do anything but comply, Tia did that, and was left weakened as the hyenas chased the Keepers off.
In the sixth book, Dark Passage, Tia helps Maleficent and The Evil Queen perform the dark ritual that would restore Chernabog to his full power and frightening form. As Finn and the others interrupt the ritual, specifically the sacrifice of Finn's non-Kingdom Keeper friend Dillard, Finn stabs Tia with her own knife. Only when it was too late did he realize that he'd been completely fooled by the voodoo queen's dark magic, that it was Dillard whom he'd stabbed, and not Tia Dalma. His grief over what he'd done, his horror at the thought of Chernabog using his friend as an appetizer, and his fury over being used so gave him the strength to knock out Tia in one punch and prompted him to lead Chernabog into the labyrinth-like passages of the temple itself.
Later, as the Kingdom Keepers arrive in Disneyland, they try to cheer Finn up by suggesting that since Dillard was killed by magical means, namely Tia's voodoo magic, then it may be possible to bring him back the same way; that they may convince her to remove the pin from Dillard's voodoo doll in exchange for her freedom.
In the seventh book, The Insider, Tia Dalma escapes confinement in Mexico by casting an illusion spell to make her captors think she hadn't. She travels to the site of Chernabog's revival, venturing into the labyrinth to seek her master. However, she used two balls of twine in the search (to make sure that she wasn't getting lost inside of it as well). Upon smelling decay, she dug through the rubble and found the corpse of Maleficent's dragon form. She took bones from the corpse, putting them in a pouch. Discovering workers drilling for natural gas, Tia used her voodoo magic to force the machine to work at maximum capacity, resulting in the labyrinth's destruction. This released the Evil Queen (whose beauty was now gone, along with much of her sanity) and Chernabog. She arranged for their transport to Disneyland through numerous supply trucks.
Having seen the destruction that was caused in rescuing her comrades, Tia Dalma decided to recreate the effect in Disneyland to burn it to the ground by igniting the natural gas with a lightning strike. She put workers in a near-by field under her control before heading back to Toon Town to confront the Keepers, who taunted her about how EVIL will always lose because it self-destructs. After the attack in Toon Town, Tia Dalma decided to take shelter in the abandoned SKyway Station; there, she used voodoo dolls to hasten her plans. Though the Keepers tried to stop her, Tia Dalma succeeded in causing an earthquake. She vanished afterwards.
Returning to what remained of her hideout, Tia Dalma began brewing a powerful resurrection spell. Among the ingredients was one of Chernabog's wings from after the lightning strike had blown him apart. The final ingredient was Maleficent's bones.
In the The Return: Legacy of Secrets, it's revealed Tia Dalma's first attempt to revive Maleficent had failed. She works for five days without sleep to bring her back, using her magic to force Maleficent's bones to knit together as a small doll, before adding a disgusting green concoction to the bones to create flesh. She add eyes and wings from bates to aid the creation of the small figure. Eventually, the figure she worked on grows into a glowing green figure in a dark mist. She begs Maleficent to come back to life, as the Keepers are getting closer to stopping them from ever existing. With those words, Tia Dalma manages to pull Maleficent free of death, albeit with her highly deformed with stronger powers. She follows Maleficent to prevent Amanda and Jess from informing the Keepers about Amery Hollingsworth Jr's plans to use Fairlies to destroy Disney, but fails to prevent Amanda from time-traveling to meet with the Keepers.