TV Wren and Book Wren are completely different characters

Alex Drake pretending to be Spencer Hastings (both portrayed by Troian Bellisario) on the series finale of Pretty Little Liars.

This is a still of Annabeth Gish on Pretty Little Liars Original Sin Season 2.

Did we ever find out who A actually was? How many A's were there exactly? Was anything in this show ever actually explained? There was so much back and forth throughout the run of this show that it's nearly impossible to even come up with a coherent synopsis for what the show was about. However, one character whose antagonistic nature seemed to be pretty stable, even when she was helping out one of the main characters, was the character of Mona Vanderwall. The geek girl, turned sexy mean girl was one of the most fun characters to follow throughout the run of the show. In flashbacks, she is often shown in childish attire, glasses and pigtails, representing her innocence at that point in time. In the main time line however, with her blood red lips, cat eyes and darker color palette, her questionable morality is clear. Ladies and gentleman, never trust a girl with blood red lips.

Spencer found out she has a lot of secret siblings including CeCe, who was born Charles.