|Relationship|| Nick Dean|
|Family||Mr. Folfax, Mrs. Folfax|
|Likes||Music, her friends and family, electronic gadgets, styling, advice, Sheen|
|Dislikes||King Goobot and his allies, Sheen constantly flirting with her (formerly).|
|Voice Actor||Crystal Scales|
Liberty Danielle "Libby" Folfax is one of the main characters in The Adventures of Jimmy Neutron: Boy Genius. She is a sassy African American girl first appearing in the Jimmy Neutron: Boy Genius film. She is Cindy's best friend and Sheen's love interest which seemed to have started in the second season. She is eleven years old (twelve starting from "The Tomorrow Boys" and onwards). She is voiced by Crystal Scales.
During the film, the first season and temporarily in "Beach Party Mummy," Libby had a green dress with blue and orange patterned rectangles on it. She also had a streak of her hair covering her right eye along with her hair in a high bun. She also had green socks with black shoes.
In "Beach Party Mummy," Libby had a new hairstyle with her hair in cornrow braids after gaining a makeover from Jimmy and her friends after Jimmy's Brain Blast to make Libby look like Queen Hasabataslapya and put the mummies to sleep for 10 trillion more years.
Starting in "The Retroville 9," Libby received new clothes. The clothes being a slight pink fading shirt, blue jeans, and brown shoes.
She also wore a swimsuit in "Jimmy on Ice" and "Beach Party Mummy."
Libby's main interest is music with the funky rhythm. When she experiences music withdrawal, she faints (as revealed in "Hall Monster"). She also loves electronic gadgets and being stylish. In the first season, she doesn't appear in the title logo. When she becomes more involved in the show, however, she is added to the logo in the second season and is still on it in the third season. Unlike Jimmy's best friends, Libby is shown to do well in school, but isn't at the level of Jimmy or Cindy in terms of intellect. According to "Nightmare in Retroville," Libby is a vegetarian.
Her favorite band is Graystar whom she has invited to Retroville twice (in "Attack of the Twonkies" and "The Tomorrow Boys"). She is also revealed to have piano playing skills (as revealed in "My Big Fat Spy Wedding" and "Vanishing Act").
Along with Cindy, Libby won a first place trophy for river stomp dancing at the school contest in "Battle of the Band;" Jimmy, Carl, and Sheen almost beat the girls with their electronic rock music guitars and drums, but at the last minute, Carl and Sheen destroyed their own instruments in a jealous quarrel, and the boys ended up with was an eighth place trophy after Carl did his giant snot bubble trick.
Libby has full knowledge about Jimmy and Cindy's relationship with each other, as Cindy does not want to express her feelings to Libby about it and stammers each time Libby mentions it. Although, Libby sometimes joins Cindy in teasing Jimmy. Libby once in a while returns Sheen's interest in herself, but not when Sheen is not annoying her with his overbearing mentions of Ultra Lord and occasional flirting.
In "The Tomorrow Boys", Libby had become the evil dictator of Retroville after Carl accidentally got the Megalomanium to her birthday party out of confusion by the perfume and the Megalomania. When she opened the present, she became mad with power, thus making her the evil dictator of Retroville.
In "The N-Men", Libby gains the super power of invisibility, based on how she was putting on vanishing cream for her acne when she and the group were exposed to the Van Patten Radiation Belt. Libby calls herself "Invisible Sister". She learned in the military station that she also had the ability to generate a force field, and create a pad to float herself in midair.
In "The League of Villains", Jimmy, Carl, Sheen, Cindy and Libby's superpowered have been mixed up. Libby is the one who had ended up with Carl's superpower; Burp Boy. This made her gain the ability to make gigantic burps enough to make anyone go flying.
Libby is probably Cindy's best friend in the School. She is always seen being with Cindy, hanging out, having fun and going shopping. They even go to each other's home for playing.
But of course, despite this, Libby is straight-minded enough to know that even some of Cindy's own absurd antics warrant a snide remark or a slight hint of disappointment from Libby (making her a bit of a foil), especially since she later on is well-aware of Cindy and Jimmy's feelings towards each other.
Libby and Sheen weren't quite close friends at the beginning, but it seems the start of their relationship was at the episode Love Potion 976/J, where Sheen was accidentally exposed to a Love Potion and suddenly fell in love with Libby. From then on, Sheen has shown obvious interest in her and is always looking after her. While Libby doesn't always approve of the nicknames which sheen makes up, she found him quite "cute and funny".
However, Libby has always stood for Sheen whenever everyone else has mocked him up. A good example is at a scene in the Yolkian dungeons in the movie.
At episode Crouching Jimmy, Hidden Sheen, Yoo-Yee thought Libby is Sheen's girlfriend, so he tried to kidnap her to urge Sheen coming to Shangri-Llama and fight him. He tried to be nice to Libby, and even "give his sister's room to Libby", but she didn't like it.
- '"Keep yellin' if you wanna mirage slappin in yo FACE!!" - Stranded
- "Sheen, none of those things do any of those things..." - Stranded
- "You can't stop da' funk...ya mamma can't stop da' funk--AH AH--yo brotha' can't stop da' funk..." - Stranded
- "Give it up for JIMMY!!!" - The Eggpire Strikes Back
- "Open your EYES, girlfriend! I'm right in FRONT o' you!!" - The N-Men
- "We hafta WHAT?!!" - Substitute Creature
- "Why don't we just go after the dog??" - Jimmy Timmy Power Hour
- "But my mama told me not to burp in public!!!" - The League of Villains
- "Ladies, there's this banking new band called Graystar and all I'm asking you is to stop walking away while I'm talking to you!" - Attack of the Twonkies
- "Yeah, or we could play 'Spin-Sheen-and-hit-him-with-a-bottle'." - Party at Neutron's
- "Meet me at the Candy Bar, Sheen, (opens door) AFTER YOU CLEAN MY HOUSE!!" - The Tomorrow Boys
- "How come I'm not invisible? (burps explosively) (covers mouth in embarrassment) Excuse me. (explosive belch) Ugh, I'm Belch (explosive burp) Boy?! (loud burp) this is way embarrassing." - The League of Villains
- "Sheen, you better put some hurting on this fool! You hear me?! This is your girlfriend talking to you!" - Crouching Jimmy, Hidden Sheen
- "Wait, stop! Carl's not an alien!" - Lady Sings the News
- "What! oh no."
- "Forgive me guys?"
- "I was listening to a good song; I have priorities." - The Retroville 9
- "Get your tounge off the floor." - The Great Egg Heist
- "Hey, Cin, put your eyes back in your head and let's get to work."-My Big Fat Spy Wedding
- Libby is one of two females in the franchise to burp, the other one is Judy Neutron Jimmy's mother.
- Libby's design in season 1 bears a huge resemblance to Keesha Franklin from the Magic School Bus
- Libby's future counterpart looks more similar to Libby's season 1 design than her current design.
- While Libby loves music, she calls Yoo-Yee's sister's CD collection totally beat.