Katarina's Shunpo is possibly a reference to a fictional technique in the popular manga series Bleach. Its name is Japanese (written as 瞬步) and means "Flash Steps," indicating that the person can move between two spots in the blink of an eye.
Katarina have many similarities with the character of the Guild Wars series Vizu in appearance, personality and skills.
When Katarina was first released, her default skin was the one that is now labeled as her Mercenary skin. This also applied to her imagery on skill icons, which can still be viewed in-game. She later had her skin, her voiceovers, and her backstory reworked.
Katarina's dance references from the last dance scene in the movie Napoleon Dynamite. The scene can be seen here.
It has since been changed; It still features the first part of the dance, but the later animation of the dance is now a punching motion with her knives that rapidly gains speed.
Katarina is one of the few champions to feature two champion spotlights due to significant changes to her kit.
Katarina's old voiceovers were similar to the new ones but were angrier. Her old voiceovers can be seen here.
Katarina's old taunt used to be, "Remember, evil spelled backwards is live. No coincidence."
Katarina's old joke is a reference to her old voice actor, who mispronounced the term "Dance Macabre". The joke refers to the Danse Macabre, or "The Dance of Death," a medieval allegory on the "Universality of Death."
Katarina is one of the few champions that had their in-game voices changed; others include Anivia and Janna.
The Red Card Katarina skin, along with the soccer skins for other champions, appeared just before the 2010 World Cup started, and were removed from the store on October 31st, 2010.
Sandstorm Katarina has a new taunt animation in which she does a backflip instead of the usual animation.
During the Maokai Art Spotlight, a photoshop tab called :File:Katarina OriginalSkin.jpg|katarina-painting1.jpg was visible. The image on the tab turned out to be a new splash art for Katarina's Classic skin.
Katarina's Chinese artwork shows her having a tattoo on her right hip. This tattoo is also visable in the Season One trailer, but not on the normal splash art.
Katarina in-game model now has a tattoo on her left side after the rework.
Katarina and Garen were the ones who stopped the inter-city brawl in Kalamanda.
According to Blitzcrank's "Fleshling Compatibility Service," a dating service made by Blitzcrank, Katarina and Garen make a perfect couple, but are not officially together. Fans have since been joking about their relationship.
Katarina once came to Demacia to protest about High Councilor Heywan Relivash's conspiracy in Kalamanda along with Jarvan IV. She was attacked but Garen defended her.