Dark Cyclone has long black hair that reaches down to her back (with brown streak in the middle of the hair since she got Aero's DNA) and green eyes. She wears a dark green shirt, a blue hoodie, dark grey jean skirt, black stockings and pink knee-high boots. Her voice is similar to Amy Rose from Sonic Boom.
As an adult, she wears a blue coat, brown vest, dark green shirt, bow tie, black trousers and electrical red boots and wears a scarf with black and green stripes. Her voice is similar to Kushina Uzumaki from Naruto Shippuden.
Dark Cyclone likes to cause misery, grief and annoyance to her half-brothers Ash and Jonathan. She's also manipulative, and uses Bryan Parker, who has a crush on her, as her pawn, and often flirts with him, and also cares about his safety. Felicity is also a highly intelligent student of Lyra Ubetcha Memorial School, as she exceeded in her class, making her a honor student, overthrowing her rival, Stephanie Logan. Like her mom, Aero, she has knowledge of engineering and mechanics, as well as superior inventing skills. Like Gravito, Felicity can handle and defend herself against bullies at her school. Robert can't bully her because, similar to Gravito, she is powerful and can easily defeat him.
In the future, Felicity has come to regret her bullying and reformed. Even though both Ash and Jonathan still have a notable disliking towards her despite her redemption, Jonathan's daughter, Heidi, and both Bryan and Stephanie, who have since married each other, believe that Felicity can use her powers for good. This would be eventually culminated in "End of the Cyclone", where she decides to sacrifice her own life to save Earth.