As revealed in the special edition of the film, when Morgana was young, she was shown to have often been criticized by her mother for not being as talented as her older sister, Ursula, whom her mother preferred. Unlike her older sister, it is unknown if Morgana was banished from Atlantica as well, but she was apparently well known as many merfolk fled from her when she first appeared and Sebastian even referred to her as Ursula's crazy sister, hinting she had previously performed questionable actions in the past that earned her some notoriety.
Despite not being as talented as her older sister, Morgana is almost just as evil as Ursula. She shows that she hates being criticized in the movie when she berates Undertow for comparing her to Ursula. Morgana is deceitful, baleful, and ruthless. She wants to steal the trident and rule the seven seas to prove her superiority over her sister. She is also depicted as having a massive inferiority complex relating to Ursula, which according to the song Gonna Get My Wish was due to their mother neglecting her over Ursula, which acted as another motive for her attempting to prove her superiority to Ursula. Morgana lacks her sister, Ursula's, deviousness and subtlety. She also is not as good as using potions as her sister was, as shown when Morgana fails all attempts to turn Undertow back into a huge shark, much to her embarrassment. Morgana is shown to have a funny, though malicious sense of humor, such as at the beginning when she grabbed Eric's advisor, Grimsby and said "Now, is that fair Gramps, I asked you". She tickled Grimsby chin with her fingers and with a nice smile.
Morgana then said, "But then whoever said we had to play fair?". Like Ursula, she is shown to be cannibalistic as during the scene, when she welcomed Melody to her lair, she offered her a plate of dead sea animals of her own species. Though Morgana's personality differs she does have the same objective as Ursula, although she is driven more by the desire to accomplish what Ursula could not rather than getting revenge on Triton. Many people think she is much less interesting than Ursula. However, despite this, Morgana is just as cunning as Ursula, if not more, as she easily manipulates Melody with her motherly-like charm into stealing the trident for her. This was due to Melody being unaware of her mermaid heritage, and that Morgana was the reason why her mother did not allow her to go into the sea until the sea witch had been dealt with once and for all.
Morgana also manages to hang on to the trident longer than Ursula. Although she ultimately desired vengeance against Ariel and Eric for their role in Ursula's death, she also at the same time hated her due to her neglect from her mother, as the latter favored Ursula far more.
Morgana appears very thin and slender, closer to a squid than an octopus. She is younger than her sister and has 8 octopus arms instead of 6. Her skin and the undersides of her tentacles are green instead of purple like Ursula's. She has green eyes, red lips, a mole on the left side of her mouth and her hair is longer than Ursula's and has pink streaks.
Role in the film
The party celebrating baby Melody's birth is interrupted by Ursula's vengeful sister Morgana attempting to prove her superiority over Ursula. She attempts to feed Melody to her shark, Undertow to force King Triton into handing his trident, but fails when Undertow is changed into a piranha and Prince Eric and Ariel rescue Melody. So, Morgana, Undertow, and her two manta rays, Cloak and Dagger escape inside a huge whirlpool of ink. While Morgana leaves, she threatens to return and have her revenge on everyone, mainly Melody.
Twelve years later, Morgana, Undertow, Cloak, and Dagger now live in an iceberg lair. Morgana is now trying several attempts to change Undertow back into a shark but all fail. Morgana now believes that it is no use and that the trident is too powerful for her to overcome. It is soon revealed that Morgana does not like being criticized because all her mother ever did was criticize her and tell her she should be more like Ursula. It is also revealed that their mother favored Ursula more than Morgana. Morgana and Undertow argue about whose fault was what about hiding in the lair. The orb light shines and Morgana goes and sees Melody holding her locket. They both get an idea. They decide they will use Melody as the tool to Triton's undoing.
Ariel confronts Melody and orders her not to go into the sea, but Melody disobeys Ariel and gets to see Morgana. Morgana sees that her time has finally arrived when she sees Sebastian's failing attempts to stop Melody from going out to sea to find out the secret of the locket. So, she sends Undertow, Cloak, and Dagger to bring Melody to her lair. The plan succeeds.
Morgana welcomes Melody to her lair, offering repulsive food, and reveals the secret of the locket. She then transforms Melody into a mermaid with Ursula's last magic potion that Morgana's been saving for a special occasion. After Melody has gone away, Undertow is angry that she didn't use the potion to change him back. Morgana sternly tells Undertow to "keep his scales on" and that she's still reeling her in. This is where she broke out in a song "I'm Gonna Get My Wish Tonight!"
Melody arrives back to Morgana's lair to thank her. After being thanked by Melody, Morgana sets the rest of her plan in motion by falsely crying. Morgana reveals that the mermaid spell is temporary. Morgana lies to Melody that "her" trident was "stolen" by a "deranged kleptomaniac" (she's referring to King Triton and his trident) and that "there is no one left to give it back for her". Melody tells Morgana that maybe she could get it back for her. Morgana acts surprised. She shows Melody a map and where the "scoundrel" lives. Melody asks if she means that it wasn't just "an ordinary fish tale" and if it really exists. Morgana says "Of course it exists. Whoever told you otherwise?" Melody tells Morgana that her mother did. Morgana responds that she's sure Melody's mother didn't mean to be cruel and deceitful. Melody says that she will bring back 'her' trident and that she can count on her. Morgana says, "Be careful, dear! Enjoy those fins!" Then she says softly with an evil grin "while you can", and chuckles sinisterly.
Morgana sees Melody, Tip and Dash near Atlantica. Morgana sends Cloak and Dagger to go and make sure nothing interferes with Melody's return.
Ariel and Flounder have followed Cloak and Dagger to her lair. Just as Melody is about to give Morgana the trident, Ariel shows up and stops her, frantically. Melody is angry and shocked that Ariel hid the truth about her locket. Morgana and Ariel are trying to convince Melody to give the trident to each other. But Melody, angry at Ariel for hiding the truth about her locket, gives it to Morgana. Morgana cackles maniacally and claims that all the seven seas are at her command. She reveals that Ariel was only trying to protect her from her. Morgana confesses that she herself tricked Melody into giving the trident to her and that King Triton is really the king and is Melody's grandfather. Melody realizes the truth. Morgana blames Melody for the theft after the girl expresses her anger over the deception stating she brought this upon her herself through her pursuit of her personal desires. Then, she imprisons Melody and Flounder into a part of her lair. She tells Melody that her time as a mermaid has just expired. Morgana then heads to the surface.
Morgana rises to the roof of her own lair on top of her new cliff. Prince Eric, his crew, and Scuttle arrive to battle the now-powerful sea witch. However, Morgana destroys Prince Eric's boat. Prince Eric and his crew are forced to stand on the ice and they survive. King Triton, his guards, and Sebastian arrive to battle the now-powerful sea witch as well. Morgana dares King Triton to hurt her, mocking his threats and then cackles. After Undertow taunts Triton, Sebastian chases Undertow, angrily but Morgana transforms Undertow into a gigantic shark and Sebastian manages to flee. Prince Eric takes his sword out and asks angrily where's Melody and what has she done with her. Morgana replies "Oh you wanna join your daughter? Well, I think that can be arranged" She commands Cloak and Dagger to take Prince Eric to Melody underwater to drown. Scuttle distracts Morgana and Ariel and Sebastian rescue Prince Eric, while Tip and Dash defeat Undertow and rescue Melody and Flounder. Sebastian defeats Cloak and Dagger.
Morgana forces all the creatures she sees to bow down to her. Melody realizes that she has to get the trident herself since Ariel, Sebastian, Flounder, Tip and Dash are forced to bow down to Morgana, and Prince Eric has been rendered unconscious. Melody realizes that she has legs and that power of Morgana cannot harm her. Morgana then forces King Triton to bow down. Morgana looks up at the sky and says to her mother that she has finally won. As Morgana sentences King Triton to oblivion, Melody surprises Morgana by snatching the trident from her. Morgana, eventually tries to take the trident away by tying up one of Melody's feet, she lifts Melody upside down and tries to grab the trident back, but Melody pierces the trident through one of her tentacles, distracting her, and Melody is free. Melody gives the trident back to Triton.
Morgana pushes Melody off the cliff after she throws the trident to Triton, but Dash saves Melody. Triton grabs his trident, says to Morgana, "Never again will you or yours threaten my family. There will be no escape for you! Ever!" and imprisons Morgana in a small iceberg, and she sinks to the depths of the sea to never be seen again. Still alive while she sinks, she whimpers "Mommy!" because she realizes that she has failed her mother by being defeated. The picture of Ursula sinks along with her, a little far behind.
- Technically, Morgana should've tried to kill Eric, because he killed Ursula, not Ariel or Triton. Either she didn't know Eric was responsible or she wanted to prove she was better than Ursula by murdering the ones whom Ursula failed in trying to kill. This is similar to the plot in The Lion King II: Simba's Pride as Zira is trying to avenge Scar by killing Simba who in the same way wasn't responsible for his death as Scar was devoured alive by the Hyenas. Zira was either unaware or ignored the truth due to her hatred of Simba.
- She appears to resemble Cruella De Vil.
- Like Ursula, Morgana also appears to have a skeleton despite having an octopus (which in real life doesn't have bones) lower body. Her skeleton appears when she is electrocuted by the trident shortly after grabbing it but is not harmed.
- She is the first villain in a film to be the sibling of another villain. The second one is Nasira as she was revealed to have been the twin sister of Jafar in the Aladdin video game Nasira's Revenge.
- Unlike Ursula, who has six tentacles despite being half-octopus, Morgana actually has the correct number of eight tentacles. However, based on her slender appearance and the fact that if you include her arms, then that actually makes her look more like a squid, which in real life has ten limbs like her.
- Her ability regarding her forcing the sea creatures to bow down to her resembled the ability Heartless Angel from the Final Fantasy series.
- In the game Disney Trivia 2: The Sequel, it says that Morgana has a polar bear guarding her iceberg lair, which, for reasons unknown, was never shown in the film.
- The way Triton and Sebastian react when she first appears implies they were fully aware of Morgana's existence the whole time but did not consider her a threat probably because of her quite poor magic skills in comparison to her more powerful sister.
- She is not mentioned at all in Poor Unfortunate Soul: A Tale of the Sea Witch. Only King Triton is mentioned as Ursula's sibling.
- Morgana is a feminine name of Gaelic origin that means "the one who comes from the seashore" or "the queen born from the sea".