Quinto says Murphy first pitched him on Thredson last year while the actor was shooting his arc on the first season of American Horror Story. (He played Chad, an interior design trapped in a turbulent, unfaithful relationship.) He knew from the start that Thredson was a monster, “which made it all the more fun for me to build the character in a way that made it seem like he was compassionate and supportive and concerned about the welfare of the patients at Briarcliff, but carrying these ulterior motives.” Of course, he’s wary of saying much more. “He carries a lot of secrets with him. He’s very intelligent. But he’s also very experienced at covering those sects and hiding them and maintaining them,” says the actor, becoming increasingly cryptic. “There’s a plan. He’s fiercely intelligent, and obviously ruthless in his willingness to create this world he’s making for himself. He’s delusional within himself. He’s not trying to sell you a story. He’s trying to believe it himself. You will learn more in the coming weeks about what motivated him to these horrific crimes.” Quinto adds he wasn’t told the entire arc of the character, and with the show’s writers still working on the season’s last three scripts, he still doesn’t know how it will wrap up. “I’m as excited to find out as anyone.” he says.
Read more at EW