Kersti is a Pixl-like Sticker Fairy in Paper Mario: Sticker Star. She is the only known Sticker Fairy. She is a guide throughout the game, acting as a tutorial in early parts of the game. Kersti grants the cut out and paste ability, which allows Paper Mario to edit the environment. She sacrifices herself at the end of the Bowser fight, transforming into a super-powerful sticker that you must use to defeat Bowser.
In both areas where Mario loses Kersti, you are unable to save the game or return to the world map. This is most likely so you cannot go to other places without Kersti.
Kersti slightly resembles Rosalina's crown as both are silver and have turquoise gems on both sides
Kersti's personality is nearly identical to that of Starlow.