Alti was an Amazon, one of the people who taught Xena in her dark days. She was an Amazon shaman driven out of her tribe by queen Cyane, because of her hunger for power. Alti was played by Claire Stansfield.

Alti commands incredible spiritual powers which have been fueled by her evil rituals performed on the slain Amazon tribe leaders. While she is very fragile in the physical world, Alti's strength lies in her psychic/spiritual abilities. The curses she place on targets have never failed; although only one instance of her curse was actually shown, as Alti curses the unborn child of Xena and Borias. She was very prophetic; and every prophecy she mentions in the show eventually happens (such as Solan never being able to experience the love of neither Xena nor Borias). She can possess living beings in the physical world (in the episode "Adventures in the Sin Trade I", Alti possesses the Berserker's horse and attacks Xena through the horse's spirit; and in the episode "Adventures in the Sin Trade II", Alti possesses a spider to bite Xena and extract information about Gabrielle).

Alti is probably best known for her trademark 'stare', which brings up pain and suffering from the target's life and unleashes the torment once again. Whenever Alti 'stares' at Xena, Xena often feels the pain of when her knees were broken, her back snapped by her Chakram (from "Ides of March"), and multiple barrages of attacks from some of her mortal enemies. However, as Alti grew in power in the series, she was able to conjure up pain and suffering from a person's future as well. This is what causes Xena to realize that Gabrielle was alive, after Alti shows Xena a vision of her and Gabrielle being crucified together on Mount Amarro.

Xena wasn't the only one who has felt Alti's powers. In "Between the Lines", Gabrielle is shown the vision of her and Xena dying; and as the vision occurs Gabrielle starts being crucified. In "When Fates Collide", Alti forces two Chinese Emissaries to envision the suffering of war.

In the few dealings with Alti, Alti claims that her powers are always evolving. In the episode "Between the Lines", Alti discovers the rich abundance of life force that can be drained from the Karmic Cycle, and says that "Here, there are generations of power, just waiting for me to take." In the episode "When Fates Collide", Alti realizes who she really was in the original world, and was able to amplify her power from both worlds. In that episode, she was able to fly, and dart across fields at an inhumanly fast speed. In the episode "Them Bones, Them Bones", Alti was able to wreck havoc on Xena, Xena's unborn child Eve, and Gabrielle from the Spiritual Realm even though according to the show's events she had been long dead. Finally, in the episode "Between the Lines", the Mother of Peace (which was Xena's next life) tells the hero (which was Gabrielle's next life) that "Alti's evil just moved on to the next life," which credits that Alti's powers do extend beyond just one lifetime.

A spiritual guide from India told Xena that no matter what happens in the Karmic Cycle Xena would always stop Alti in every lifetime as soon as Alti discovers her powers. This has been true; in each episode that featured Alti, Xena stops her before she could do anything else.

Alti trained Xena as a shaman and seduced her with the promise she would become the Destroyer of Nations. This finally led to Xena murdering Cyane and several other leaders of the Nothern Amazons. Xena escaped from her when she became pregnant with Solan, but not before her unborn child was cursed by Alti.

In Season Four, after Gabrielle had fallen in Dahak's lava pit with Hope, Xena travelled to Nothern Amazon territory and defeated Alti.

Xena had numerous encounters with Alti over the course of the show. They crossed paths in India (where Xena was told she would always be there to stop Alti in any future lives). Alti appeared again when she tried to take over the spirit of Xena's unborn child in Season Five and next in Season Six when she cloned Xena and Gabrielle into the present time. Her final appearance was in "When Fates Collide" as the High Priestess of Rome in an alternate reality.