- "Willful ignorance. I remember that, almost let me sleep some nights."
- ―Peacock bitterly reflects his work for Murkoff
Simon Peacock is a mysterious character who appears at the very end of Outlast: Whistleblower. Following his escape from Mount Massive Asylum, Waylon contacts a man who's associated with an independent journalist organisation and media leaking website. After going over the asylum's footage and assuring the Park family of their safety, Simon informs Waylon of what kind of damage his video recordings can do to Murkoff, but notes that he'll end up as one of their prime targets, as a result. Waylon ultimately decides to take the risk and upload the video despite Simon's warnings.
Simon apparently dies some time after the leak occurs.
In Issue 4 of the Murkoff Account, it is revealed that Peacock is still alive  when Paul Marion and Pauline Glick encounter Peacock near Miles' apartment. Paul chases Peacock down, and after a short discussion where Peacock questions Marion's intentions as a Murkoff employee and bitterly reflects on his own time with the company, he gives Paul coordinates that are revealed to lead to the Temple Gate compound.
Despite being shot by Pauline multiple times, Peacock is unaffected and continues to fight both her and Paul. During the fight his cloak is pulled off, revealing a ragged, corpse-like body. Having taken an imprint of Marion's jaw under the guise of attacking him with the Styrofoam block, Peacock successfully escapes from the two agents.
Later, he (and perhaps Waylon) kidnap Marion's daughter, which prompts Marion to fall into a trap, is captured and then disappears. Later, Peacock questions Marion on the whereabouts of Miles Upshur and William Hope, and explains that imprinting religion onto someone works just as effectively as the Morphogenic Engine torture does. He then makes a little prayer, and the issue ends.
- "You press that button, there's no going back, Mr. Park. There's enough hard evidence in that video file to make a world of shit for our friends at Murkoff. You got out of Mount Massive alive, and we've done everything in our power to cover your tracks, but our enemies are twitchy and malicious corporate paranoiacs with resources you're too moral to imagine. You won't be the only target. Anyone you care about, your wife, your child, they'll be nothing to Murkoff but ways to hurt you. I need you to understand the bridge you're crossing here. You will do irrevocable damage to the company, you might even get close to something like justice. But. Once you click upload, your life is over. Everyone you love is fucked. But it's the right thing to do. Is hurting Murkoff worth that much to you?"
- "Mount Massive was a pebble in a pond, an expermient on individuals. This is where the real sickness spreads."
- "How do you sleep? How do you justify working for people you know are evil?"
- "I need your help. I need somebody still inside Murkoff. I'm not asking, I'm telling you: You're going to help me."
- Simon's named after his voice actor. His initial name, Julian, was never mentioned in the game, but rather found in the game files.
- His initial name (Julian), the Australian accent and being associated with a website that provides news leaks is a reference to Julian Assange, a journalist and a co-founder of WikiLeaks.
- Simon's website, VIRALeaks (a portmanteau of "Viral" and "Leaks"), is a reference to an international, online, non-profit, journalistic organisation called WikiLeaks which publishes secret information, news leaks, and classified media from anonymous sources.
- His in-game character model is recycled from one of Murkoff's background characters.
- Simon is an ex-member of Murkoff Corporation, who 6 years ago prior to the start of Outlast leaked several materials from company and encouraged other whistleblowers from the company to do the same.