Quinto, a 1995 graduate of Central Catholic High School and a 1999 graduate of Carnegie Mellon University who grew up in Green Tree, appeared in the first season of “American Horror Story” as a completely different character. So did his co-stars, Jessica Lange and Mr. Peters. (“AHS” was renewed last week for a third season but so far Ms. Lange is the only actor attached to return as yet another, different character.)

In last week's episode, Thredson was revealed to be Bloody Face, a serial killer of women whose crimes authorities attribute to new Briarcliff Manor resident Kit Walker (Even Peters).

But in FX’s “American Horror Story: Asylum” (10 p.m. Wednesday) he got a chance to establish his character Dr. Oliver Thredson as a good guy – or at least, as a sane guy among patients and their abusive keepers in an insane asylum – before pulling the rug out from under viewers’ expectations.

SPOILER ALERT: If you have not seen last week’s episode of “American Horror Story” and want to be surprised, read no further.

Quinto, who is probably best known for re-creating the role of Spock in J.J. Abrams’ “Star Trek” reboot -- the sequel, “Star Trek: Into Darkness,” will be in theaters May 17 -- said he knew from the beginning about Dr. Thredson’s true nature.

“It was part of the conversation that I had with [executive producer] Ryan [Murphy] about me coming back to the second installment of the show,” Quinto said in a teleconference with reporters last week. “I felt like my responsibility became to create a character that people could trust, or at least trust initially, and have some hope that perhaps he is actually the one voice of reason and sanity within this chaotic world. So it was actually more exciting for me to know from the beginning. It gave me more to play with and more to hold back and more secrets to keep.”

Quinto said that opportunity to build up the character in one direction before the reveal set this particular role apart from past villains he’s played.

“Any time an actor revisits territory that they’ve been in before, it can be a source of trepidation, as it was for me,” Quinto acknowledged. “But part of the reason that I loved what the opportunity stood for was that I got to know, going in, I got to really build something. With ‘Heroes,’ that character was built before I was ever attached to it. There were eight episodes of anticipation that were built before you met Gabriel Gray in ‘Heroes,’ but I had no participation in that.

“For me, it was really exciting to get to go in and having all the information, and actually be that part of the process of creating a character,” he continued. “That, to me, was a difference. That, to me, was something that I thought, yes, that makes sense, and it also has a similar structure to the journey that I had on ‘Heroes,’ at least the introduction or the reveal, as they say; which proved very effective in that scenario and I felt I could really also serve this story in this particular innovation as well.”

Quinto said he liked that his Thredson character is more grounded – no super powers – than Sylar/Gabriel Gray on “Heroes” and that “AHS” offers actors an opportunity to play a role for a limited period of time.

On most TV shows, actors sign multi-year contracts that lock them in. But because “AHS” tells a different story in each 13-episode season, actors just have to commit to a role for a few months of filming.

“It’s attractive in a different way for somebody that’s used to doing features and used to having more flexibility with their schedules,” Quinto said.

Wednesday's episode, “The Origins of Monstrosity,” delves into the roots of the characters in “Asylum,” Quinto said. “A lot of things will become clearer and probably even more disturbing in the next couple of weeks.”

That includes the motive behind Bloody Face’s killing spree.

“It all traces back to one source of trauma that then sort of branches out to include all of these unfortunate women,” Quinto said. “The storytelling structure of ‘Asylum’ is really going to pay off in a really big way. All of the questions that people have, and that the episodes that are airing right now are generating, will definitely be answered. That’s my instinct, at least, having read up through almost the end now.”

"AHS" episodes will continue airing through Dec. 12 then take a two-week break, returning Jan. 2 for the final four episodes of the season.