In contrast to Neptunia's sometimes dumb and irrational behavior, Anti-Neptunia is smart and determined in her ambition to become more powerful so she can cause even more bad luck among humans, an ambition shared by all her Anti-Fairy friends. She is married to Anti-Astronov, and sometimes seen flirting with other male Anti-Fairies, especially her former ex-lover, Anti-Cosmo, sometimes lamenting that she should've married him. Anti-Neptunia also flirts with Timmy on a few occasions, for example, in her debut episode, she disguised herself as Trixie Tang and gave Timmy "good luck kisses", which actually gave him bad luck. While Anti-Neptunia is fond of Foop, she dislikes how he always steals the spotlight of his parents. Similarly to Trixie, whenever she's not working on a nasty scheme, Anti-Neptunia occasionally gushes over her prettiness. She can easily manipulate anyone to do her dirty work, whether it's by shapeshifting into someone or other tactics. Anti-Neptunia also had the power to hypnotize her enemies and allies, something that usually takes thousands of years of practice, according to the Anti-Fairy Council. Yet, she'll also hypnotize herself if she accidentally sees a reflection of herself while her eyes are still in a hypnotic trance.
Anti-Neptunia has a dark and blue color scheme, bat wings and a black crown like all Anti-Fairies. She wears a dress and heels, like her opposite counterpart, aswell as black gloves, her hair is shorter, and she has fangs for teeth, like Anti-Cosmo. Anti-Neptunia also speaks with a cultured British accent.
Anti-Neptunia didn't give birth to Anti-Sunny, who was instead born from Anti-Astronov.
Much like Anti-Cosmo, Anti-Neptunia has a British accent, while Neptunia does a terrible British accent.
Neptunia has long hair, while Anti-Neptunia's is short.