Mona Vanderwaal is one of the main characters of the upcoming series, Pretty Little Liars: The Perfectionists. She is portrayed by Janel Parrish.
Mona Vanderwaal is a character on Pretty Little Liars. She was the main antagonist of seasons 1 and 2, the secondary antagonist of season 3, an anti-hero in season 4, the initial main antagonist turned heroine in season 5, and an anti-heroine in seasons 6 and 7. She is also the main antagonist of the first four books of Pretty Little Liars book series.