"Breaking news. Extermination day is canceled. Charlie Morningstar managed to fend off the angelic attack with more than just nice words. In unseen turn of events, our demonic head honcho Lucifer stepped in to save his daughter's ass in the last moment. We're also hearing reports that Adam, leader of the Angelic Legions, first man and totally fuckable bad boy, has been slain by a filthy janitor. The janitor said, quote, "Charlie told me to stab, so I did". Anyway, congrats to Charlie and her crew for not being totally fucking useless for once."

*She is a supporting character and a minor antagonist who made her debut in the Hazbin Hotel pilot.

Katie is a tall, very thin, white-skinned demon with a long neck that mirrors her torso. She has a large round head and short blonde hair in a neck-length bob cut styled to flair out into an almost fan-like shape with lighter-colored streaks, and bangs that are swept to the side.

Her eyes have rose-colored sclera and normally non-visible white pupils, and she also has red lipstick on her lips for makeup.

Her attire consists of a set of pearl earrings, a matching pearl-choker necklace around her neck, a black-trimmed rose blazer with a sweetheart neckline and enclosed by two black buttons, and a simple black pencil skirt.

In her Full Demon form, she reveals an extra pair of eyes, which, alongside her original pair of eyes, glow bright red. She also summons two extra pairs of arms that resemble the front legs of a praying mantis, right below her usual pair of arms. She also gained sharper teeth.

Katie is arrogant, selfish, and narcissistic. She openly derides Charlie's plan to rehabilitate Demons. She cares mostly about her own image, the hottest stories, and the latest gossip.

She doesn't seem to care about, or even acknowledge Charlie's royal position in Hell, and openly expressing contempt for her and her ventures. She has also been shown to be homophobic, refusing to even shake hands with Charlie, claiming she "does not touch the gays" due to her "standards", although she did immediately proceed to poke the latter several times.

Katie is aggressive and seems to always be on edge. She deliberately spills hot coffee on Tom's crotch, while insulting and threatening Charlie. At the same time, Katie does not tolerate insults in her direction, and when Charlie snaps and calls her a bitch, Killjoy instantly falls into a rage and rushes at the princess with her fists.

In "The Show Must Go On", she was willing to acknowledge Charlie, Lucifer, and Charlie's friends for fighting against the Angels and having the Extermination Day cancelled, saying that they were "useful for once".*