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Zhan Tiri is an evil warlock and the true main antagonist/Bigger Bad of Disney's Tangled franchise, being an unseen antagonist of the film and the overall main antagonist of Tangled: The Series. He was first mentioned by Xavier in the episode "Queen for a Day", and made his first appearance in "Painter's Block".
In the kingdom of Corona's myth, Zhan Tiri was a powerful creature who unleashed an all-consuming blizzard on the kingdom that destroys everything in his path. The only one who was able to stop the evil warlock was a man named Lord Demanitus. Using magic and science, Demanitus built a giant device strong enough to change the storm back into the direction of Zhan Tiri to imprison him and his disciples, saving Corona from the warlock's wrath. But Zhan Tiri's defeat did not leave him abated; his magic storm remained in Corona as a curse that waited for Corona to be at its weakest and strike again.
In "Queen for a Day", after Rapunzel's parents' attendance to the anniversary of their marriage, Zhan Tiri tried to destroy the kingdom of Corona with a snowstorm that makes the princess high difficulties to keep the people of Corona safe. When King Frederic and Queen Arianna went to a mountain with Maximus, a frozen spike fell near him and the king and the queen fell with the coach. Meanwhile, Maximus returns to Corona to tell Rapunzel about the incident of her parent's in the mountain.
The next day, Rapunzel told to the advisor Nigel that she must to go to save her parents, but Nigel tells her that she can't leave the kingdom because she was the queen and the time was too serious, then Eugene tells her that he, Lance Strongbow and the Pub Thugs can go, but Rapunzel was too worried for them, the Captain of the Guards left her to decide and Rapunzel leaves them with broken-hearted to go. After she "turns back" to Varian, Rapunzel sadly ordered to the royal guards to evacuate the island.
Then, Rapunzel, Pascal and Cassandra go to Xavier's store to find the Demanitus' device that saves the kingdom and stop Zhan Tiri.
Zhan Tiri's makes his physical appearance in the episode "Painter's Block", in which one of Zhan Tiri's spirit allies, Sugracha the Eternel, managed to escape their prison, and formed a plan to free him as well. Zhan Tiri was close to being freed, until Rapunzel, whom Sugracha had under her spell, broke free from it and made sure that her master would remain in his prison.
He was once again mentioned in "Rapunzel and the Great Tree" where it is revealed by Adira that Zhan Tiri took over the Great Tree and used it as is a base to stop anyone who approached him, but Lord Demanitus but a stop to him and rendered the Evil Magic in the Great Tree dormant
In "Rapunzeltopia" one of Zhan Tiri's servants Tromus under Zhan Tiri's orders is trying to keep Rapunzel inside The House of Yesterday's Tomorrow so that Zhan Tiri can have the sundrops power so he can escape Tromus traps Rapunzel in a dream world were she never touched the Black Rocks, if Rapunzel accepts the Dream World the power will be transferred to Zhan Tiri represented by a Statue, but Rapunzel breaks free of the dream world causing Tromus and the House of Yesterday's Tomorrow to vanish into oblivion foiling Zhan Tiri
In a flashback in "Lost and Found" it's revealed that Demanitus pupils (Sugracha the Eternel, Tromus and probably Mother Gothel) betrayed him to serve Zhan Tiri and summoned him once again
Zhan Tiri is known as an extremely sadistic, malevolent and sinister warlock who will not hesitate to destroy absolutely everything in his path.
He is considered by many fans to be the most evil villain in the Tangled franchise as he has no revenge seeking motive neither does he have a tragic backstory.
A small model of Zhan Tiri is seen in the second season's episode "Keeper of the Spire", as one of the museums' exhibits.