Queen Kylie is the antagonist in series 3 and the leader of the Citadel. She is the main enemy of the Sparticles and Sensitives. Her brother, Erimon, also works in the Citadel along with his love interest Dora, Fizzy and Fizzy's teen dad.
Like how Fizzy did when he was emperor, Kylie also wears a crown. Her hair is styled in an 1980's style (which is the decade that she's from). She often wears crazy outfits.
Kylie has a scar on her neck from when she was accidentally pushed through a glass plate window by her brother, she was apparently bullied at school because of her scar where they called her "Scarface". Before Kylie is returned to her home decade, her scar is removed by Aris' powers.
In "The Neuroscrambler" Kylie says that she won the First Teen War, which is a battle that took place between series 2 and 3 that Ernesto also fought in alongside his teen dad, Rat, and The Resistance. It's likely Holly, Sadiq, Reese, Frankie and Serena where already imprisoned in the Citadel when the war took place or were imprisoned shortly afterwards.
Kylie accuses The Sparticles of deliberately causing the Quantum Nexus mix up which caused the teen parents to appear and often subjects Holly, Sadiq, Reese, Frankie and Serena to food peltings while they're imprisoned. She also claims to the country the Sparticles have ruin her life for bringing her to present day, but she admits to Dora that she loves the world she's in because of the power she has.