Mamanu is the main antagonist of the Sofia the First episode "The Emerald Key". She is even much crueler than Princess Ivy in her character attitude, thus being portrayed as an outright villain.
Mamanu is arrogant as an evil trickster by disguising herself as Lani, a Hawaiian princess. She is even despicable, notorious, while in a conflict with the other Lani.
The Emerald Key
Mamanu was very notorious for being a despicable thief by snatching magic stones in the island of Hakalo. This results in the evil sorceress to be banished from the island of Hakalo, thus being the invader of Enchancia. Another despicable plan is stealing the Emerald Key, which belongs to a Hawaiian princess named Lani. This made her very angry, which put a stop to the evil thief.
In order for her to obtain the key, Mamanu disguised herself as Lani, which got her into a conflict between the real Lani. King Roland II was very angry about the fake and real Lani, which puts the two on a test. She won the final test at waltzing, but failed after getting angry at the snail. Another despicable plan was when she put an attempt to make Lani tired to win the final test after failing a make-up test.
She and Lani went out of the maze in their intelligence. However, she was eventually very despicable and notorious by cheating in order to win the reward. This results her to escape the maze. In order to stop the sorceress, Sofia and the Royal Family went after the thief. Also, the forest animals are summoned by Clover (the rabbit) to stop the evil thief. While surrounded by the animals, the king tried to capture her. The key is retrieved by Lani, which made the king summon his guards to arrest her. She ends up escaping by vanishing and is never seen again.
Mamanu on DisneyWiki.