There have been many shocking turns in the plot of the "American Horror Story" franchise, but none quite so fiendish as the big reveal of the 10 Commandments Killer and the story of the killer's rise.

According to TV Guide, the show is notorious for taking certain elements of the characters and twisting them into macabre versions, leaving the audience sincerely disturbed with each new revelation.

Such was the case during Episode 8 of Season 5, titled "The Ten Commandments Killer," when the show finally revealed the killer. More importantly, audiences learned what the killer had done to get to this point.

There are major spoilers ahead and you should only continue reading with that in mind. 

The latest episode revealed that John (Wes Bentley) is the killer. Here is how the big reveal played out.

When the Countess' (Lady Gaga) daughter Wren commits suicide, John is lured back to the Hotel Cortez demanding answers. Sally (Sarah Paulson) is reluctant to help him, but she finally gives in and decides to show him where the killer has been staying in the hotel.

It seems the killer has one specific room, where he prefers to hide out. Sally takes John to room 64, which she claims is the killer's den. But John has been staying in the very same room, leaving him totally baffled. 

John is clueless how the killer could be hiding there until Sally shows him a hidden room behind the armoire, which contains the killer's mementos dating all the way back to the 1920s.

Although he is clearly alarmed by the hidden room, John is much more concerned about who let the killer into his room. But therein lies the twist: When John checked into the room, he let himself in.

As it turns out, John's blackouts were sinister. Though he could not previously remember the moments, the memories start to come flooding back to him. John is revealed to be the 10 Commandments Killer, which has dark implications for the story behind the fate of his own son.