Kitty is Johnny 13's girlfriend and an antagonist in Danny Phantom.
History
13
Her first appearance was in the episode "13". When she got injured trying to get through the Ghost Portal, she empowered her jacket, ring and scarf so that whoever wears them will be possessed by her. Johnny gave them to Jazz, until Danny stopped him and caused Kitty to remain stuck in the Portal.
Lucky In Love
She possesses Paulina and uses her to date Danny to make Johnny jealous when Johnny became attracted to other woman during their visit in Amity Park, Danny himself has no idea that Kitty was possessing Danny the whole time. Eventually when Danny discovers this he and Johnny stage a fake fight so that Kitty can leave Paulina's body and go back to her old boyfriend, the plan works but Johnny accidentally reveals their scheme which upsets Kitty.
The Ultimate Enemy
Kitty and Johnny appear in the special as on of the Ghosts affected by Dark Danny.
Christmas Episode
Kitty, Johnny, Shadow are amongst the ghost that help Danny save Christmas.
Girl's Night Out
After another fight with Johnny, Kitty teams up with Penelope Spectra and Ember McLain who also had a fight with their respective boyfriend) and goes to Amity Park to eliminate all men displaying Misandristic Tendencies as they do so, she then caught's Johnny eying another girl and Johnny tries to run away but she knocks him off his bike and she blows a kiss at him but ember uses on of her powers on her guitar to make the kiss bigger effectively eliminating all of them men including Dash Baxter, Kwan and Tucker Foley, with Danny and Jack out of town it is up to Sam, Jazz and Maddie to save all the men before there all gone permanently.
Phantom Planet
She, among all the other ghosts in the series, appears at the end of the series helping Danny save the earth from the disasteroid by making the earth intangible saving the Earth as well as the Ghost Zone as well.