The 'Pretty Little Liars: Original Sin' Finale Officially Unmasks "A" (SPOILERS)

Spoiler alert: This article contains MAJOR spoilers for the Season 1 finale of Pretty Little Liars: Original Sin.

Throughout the entire first season of Pretty Little Liars: Original Sin, the all-new generation of little liars were up against one menacing threat: "A." Unlike its Freeform counterpart, this assailant was more ruthless than ever, piling up ghastly kills and a massive body count that rivals anything Michael Myers has ever done.

After spending all of our time theorizing about who is terrorizing the fictional town of Millwood, the season finale officially unmasks the identity of "A" and let us just say this — we could have never predicted this outcome.

So, who is "A" in Pretty Little Liars: Original Sin? Keep reading to find out!

As the little liars roam the Waters' house to look for clues regarding the identity of "A" and his connection to Angela, they receive two texts that lead them to their school, Millwood High. Once there, the girls have the opportunity to punish their bullies, but none of them follow through, ultimately deciding to show mercy.

They soon reunite and head to the auditorium, where they find their mothers tied to chairs. The girls scream and run toward them, only for the moms to order them not come any closer. "A" soon emerges from the side of the stage, and Imogen (Bailee Madison) want to get some answers. She asks if he's Angela's brother, and in a twist no one could've anticipated, Principal Clanton (Robert Stanton) confirms the suspicion as he walks across the stage while holding a gun.

After Principal Clanton announces that "A" is Angela's twin brother, Archie, he reveals that Angela was his daughter and Archie is his son — we don't know about you, but we truly did not see this coming!

The little liars and their mothers don't understand, so Principal Clanton decides to explain how this all came to be. He reveals that grew up in Millwood and was classmates with Rose Waters (Jeanette Bonner).

As teens, the pair sang in school choir together; Rose eventually took a liking to him, and after spending time together, she became pregnant with twins. Since Principal Clanton's parents didn't approve and Rose's family desperately needed money, his family paid her family off to move to another town, never to return.

Clanton stayed in town and became a teacher at Millwood High, eventually working his way up to vice principal. Now, that's when Rose returned to Millwood; she wanted Angela to attend Millwood High and receive a decent education.

Imogen soon interrupts the story, asking Principal Clanton why Archie didn't attend school. He relents that Rose wanted to keep Archie at home, as he had "a face only a mother could love." Ouch!

Rose and Clanton understood that no one could ever know about their past, so he watched his daughter walk from class to class everyday with Davie Adams and her vicious clique. Unfortunately, Angela died by suicide; however, Principal Clanton reveals that it wasn't due to her sexual assault but because of the moms and their desire to "erase" Angela from existence.

All 10 episodes of Pretty Little Liars: Original Sin are now streaming on HBO Max.