Princess Unikitty lives in Cloud Cuckoo Land, where she and the Master Builders reside in safe and secret harmony, even though they know it is a matter of time before that ends. Some things Lord Business and Robo SWAT do make Unikitty short-tempered, but she will do anything to help Emmet and the Master Builders stop Lord Business from gluing the world with the Kragle.
Unikitty is the happy-going spirit of Emmet's oddball group, and thus susceptible to strong emotions. She feels so strongly for her friends that anything that happens to them she is effected as well. Because of this, she sometimes has a hard time controlling her emotions to "stay positive". But, when it comes to protecting those she cares about from those doing harm to them, she does not hold back. At all.
She first greeted Emmet and the gang in Cloud Cuckoo Land and took them to the "dog", which was a temple where the Master Builders were gathering. However, after they were attacked by Bad Cop and the Robo SWAT force, they were forced to escape underwater, much to her devastation in seeing her home destroyed. She then joined the plan to infiltrate the Octan Tower, disguising herself as Biznis Kitty, until being captured at the last second. Soon the gang escaped, and in the battle of Bricksburg, Emmet was attacked by Micro Managers which made Unikitty angry enough to lose control of her normally happy demeanor. Unleashing her fury on the robots, she provided the distraction needed to help Emmet get to the Kragle-izer.
Upon the Kragle-izer's destruction, Unikitty is seen celebrating with the group, along with the rest of Bricksburg.
- Uni-Kitty became friends with Fluttershy when she let her stay in her Cottage and she currently lives there.
- Uni-Kitty has a younger brother named Puppycorn.
- In The Lego Movie (and its 4D short) and Lego Dimensions, Uni-Kitty is voiced by Alison Brie, while on the TV series of the same name, she is voiced by Tara Strong (who voices various characters, including Timmy Turner from The Fairly OddParents and Twilight Sparkle from My Little Pony: Friendship is Magic).