She looks and sounds like the real Sofia, but her personality is the complete opposite. Instead of being kind and caring, she is a badly behaved little girl who likes to cause trouble and wreak havoc just for fun.
Role in the Series
In her debut, Bad Sofia appears after Sofia creates her with Cedric's copying spell so she could go to the Highland Hootenanny and keep her promise to show Lady Joy around the castle at the same time. Sofia gives her a doll and tells her what to do which she happily agrees to. After Sofia leaves, she reveals her true colors as an evil twin to Clover who realizes Sofia messed up the spell when she made her. When Clover tries to go warn the real Sofia, Bad Sofia grabs him, locks him into Wormwood's cage, and runs off to where she meets Joy. After the real Sofia leaves, Bad Sofia causes trouble throughout the castle until she finally gets bored with Joy and ditches her so she can go to the Hootenanny.
At the Hootenanny, Bad Sofia bumps into the real Sofia who asks her what she's doing here and who's playing with Joy. Sofia the Worst tells her she's here to have fun and who's playing with Joy is her problem. After Sofia tells her she's not being very nice, Bad Sofia tells her "That's because I'm not very nice. I'm a bad Sofia." She then proceeds to tell the real Sofia "You can call me Sofia the Worst." She then throws the entire Hootenanny into chaos until the real Sofia throws her into a barn and locks her in.
Bad Sofia escapes and follows the real Sofia back to the castle where she causes even more trouble by knocking over Gilbert's bridge model, mocking Sofia's clumsiness. The real Sofia, Joy, and Cedric chase her into the meeting where everyone finds out about the two Sofias. After Roland asks what's going on, Bad Sofia points at the real Sofia and states "She made me." The real Sofia admits she did it so she could be in two places at once. At the real Sofia's request, Cedric undoes the spell that created her and Sofia the Worst ceases to exist, vanishing in a puff of smoke.
Her name is likely a reference to the lyrics in the song from Robin Hood, "The Phony King of England": "Too late to be known as John the First, he's sure to be known as John the Worst".
The only difference between the real Sofia's and Bad Sofia's appearances is that the real Sofia usually wears a purple dress while Bad Sofia's dress is pink, due to the duplication spell being cast incorrectly. If the spell had been cast correctly, then she would've had a purple dress. Plus, Bad Sofia removed her amulet and gave it to Joy.
In the book Sofia the Second, Bad Sofia is referred to as Pink Sofia due to the color of her dress.
Strangely, Bad Sofia was able to understand Clover despite her amulet not being real. It may be that Sofia was able to give her copy her powers when she cast the spell.
"Ha! Just kidding!"
"No, I can say whatever I want, just like you."
"I suppose you're about to tell me!"
"Sounds like fun! I'd love to."
Clover: "You really are rotten." Bad Sofia: "To the core."
"Going to the dance was the way better part of this deal."