That's it, Kronk! That's it! I'll get rid of Kuzco! Hahahaha! (Kronk: The real Kuzco?) Ha- Of course, the real Kuzco! Don't you see? It's perfect! With him out of the way, and no heir to the throne, I'll take over and rule the empire! Brilliant!
~ Yzma plotting her revenge against Kuzco.
It's brilliant, brilliant, brilliant, I tell you! Genius, I say!
~ Yzma referring to her plot to kill Kuzco.
It's called a cruel irony... like my dependence on you.
~ Yzma to Kronk.
Yzma is the main antagonist of Disney's 40th full-length animated feature film, The Emperor's New Groove, and its television series, The Emperor's New School, and the sole antagonist of its sequel, The Emperor's New Groove 2: Kronk's New Groove.
She's a hideous old woman who wants to usurp the throne by murdering Emperor Kuzco. She also has a strong, but rather dimwitted henchman named Kronk (voiced by Patrick Warburton). She's also a rather diabolical, intelligent, and manipulative alchemist who concocts various potions and unguents.
She was voiced by the late African American singer, Eartha Kitt, who also played Catwoman in the 1966 Batman television series episode, "Dressed to Kill". She appears in other media as a cat.
Yzma's seen to be malicious, unpleasant, but comically eccentric, often calling herself beautiful even though all other characters in the series consider her appearance revolting. She is a complicated and impenetrable thinker; one example was her original plan to kill Emperor Kuzco (which was to turn Kuzco into a flea, put him into a box, put that box into another box, mail it to herself, and when it arrived, in her own words, "I'LL SMASH IT WITH A HAMMER!!!").
Yzma's described to be "scary beyond all reason". Yzma's color theme was stated to be purple, being that purple is a color often associated with evil. Purple's also the color of royalty, showing Yzma's ambition to be an empress. Additionally, purple carries connotations of madness, alluding to her insane lust for power. Her character's also surrounded with animals like snakes and cats, which are considered to be signs of evil in numerous religions throughout the world.
Yzma's also shown to be quite intellectual and knowledgeable in chemistry, but she can also be somewhat unqualified and incompetent with it, as she accidentally uses extract of llama on Kuzco, thinking that it was poison due to mislabeling.
Kingdom of the Sun
In the original draft of The Emperor's New Groove, Yzma is an elderly woman who seeks immortality and permanent youth by blotting out the Sun with the Incan god of darkness Supai. In the climax, she and Supai met their deaths when Pacha lassoed the Sun towards the Earth. Despite the film never seeing the light of day, some elements of this film were incorporated into others.
The Emperor's New Groove
Yzma was originally Emperor Kuzco's royal adviser. However, Kuzco didn't like the fact that she apparently did most of the governing behind his back, so he decides to fire her. Yzma furiously planned to dispose of the emperor and rule the empire in his place by poisoning him. This backfires when Kronk accidentally mixes up vials in between the poison and a potion that turns the drinker into a llama, resulting in Kuzco becoming such an animal.
After Kronk incapacitates Kuzco, Yzma orders Kronk to take him out of the city and dispose of him. The next day, after being informed of Kuzco's "death", Yzma arranges a (very half-heartedly) funeral for him, and quickly concludes it by replacing Kuzco's image with her own and establishing herself as the new ruler of the empire. When Kronk lets it slip that he let Kuzco live and get carted away by a local peasant, Yzma and Kronk set out to silence Kuzco for good before word can get out that he's still alive.
She follows Kuzco into the jungle, and finally catches up with him in her lab. She attempts to kill him and his ally, Pacha, but her plan backfires again when she accidentally drinks one of her potions, transforming her into a harmless kitten. At first she gains the upper hand and grabs the human potion before Pacha and Kuzco could grab it, only for it to be knocked out of her hands into Pacha's when Kronk opened his trapped door and crushed her. In the end, she is placed in Kronk's Junior Chipmunks class.
Kronk's New Groove
Yzma plays a very little part in the sequel. She just somehow returned to human form, although she still has a tail. She tells Kronk that she's no longer evil and involves him in a plan to sell youth potion to the old people. Unbeknownst to Kronk or the old people, the really snake oil of the "youth potion". As soon as Kronk figures this out, he and Rudy inform everyone as they're about to elect Yzma emperor. The old folks chase Yzma and corner her on a bridge above a river full of alligators. However, Yzma drinks a potion to transform into a cute bunny rabbit, so that no one will want to attack her. However, she is caught and taken away by a falcon.
At the end of the film, Yzma is shown to be taken to the bird's nest, where its two eggs hatch and presumably eat Yzma, as they are shown about to attack her before the credits roll.
The Emperor's New School
In this TV spin-off, Yzma, having survived her encounter with various Hawk chicks and regained her human form, once again plots to take the throne from Kuzco. The show's premise is that Kuzco must attend school and pass all of his classes in order to remain Emperor. If he fails even one class, he'll be unable to retake the throne. In order to make Kuzco fail, Yzma poses as Principal Amzy, the principal of Kuzco Academy. With the assistance of Kronk, she comes up with various schemes (most involve potions that transform Kuzco into an animal, similarly to the film) in order to make Kuzco fail one of his classes. Several episodes reveal members of Yzma's family, including her mother Amza who (according to Yzma) nags her incessantly, forcing Yzma to carry out her plots. Yzma also apparently has siblings, as she has two nephews: Zim and Zam.
Once Kuzco became emperor again in the series' finale "Graduation Groove", Yzma was demoted to Kronk's secretary by Kuzco's order.