* Original "A": The first "A" is revealed to be Mona Vanderwaal, the seemingly quirky and harmless girl who was initially considered a friend of the Liars.
* "A" after Mona: Mona's reign as "A" doesn't last forever, and the mantle is taken up by Charlotte DiLaurentis (CeCe Drake).
* The "A" Team: Later, we learn that Charlotte worked with Alison DiLaurentis, the missing girl at the center of the show, and other accomplices to torment the Liars. This group is referred to as "The A Team."
While it seems simple, the identity of "A" is full of twists and turns. It is important to note that the show plays with the idea of the "A" identity and the motives behind it, creating a mystery that unfolds throughout the series.