The Man

Five Nights at Shea's
The Man can only be found in the secret Night 9. It can be accessed by clicking on the shadow in the game over screen.

He will either begin in Cam 1 or Cam 6. If he's in Cam 1, he'll travel down the left hall. If he's seen in Cam 11, Shea should shut the left door as quick as she can. If he starts in Cam 6, he'll travel down the right hall. If he's seen in Cam 12, Shea should shut the right window as quick as she can. Failing or neglecting to do these actions will make The Man enter the office, and attack Shea, with the most detailed animated jumpscare in FNaSh 1.

Five Nights at Shea's 2
The Man stays in Cam 9 behind a table. To keep him in check, Shea must keep his music box playing to keep him calm. Though, letting the music box wind all the way down will cause the music to stop playing, and he'll slowly stand up. Winding up the music box will also cause the music to stop playing, so Shea can't be too effecient or too ineffective. If The Man manages to leave the room, he will attack Shea shortly after, resulting a game over.

Five Nights at Shea's 5: Halloween Edition
The Man can be found on the secret Night 12. (it's currently unclear how it will be accessed) If Shea sees him in her Night Vision Camera, closest to the door on either side, she should run up to the door and hold it shut until she hears The Man walking away. Failing or neglecting to do so will make him attack Shea, resulting a game over.

Five Nights Before Shea's
"You know what, I have no comment."

This part of the article is non-canon, meaning it is completely separate from the FNaSh story and timeline. Theories should not be proposed under this.

The Man is not present in the normal nights. Instead, he activates on Night 13 on Hard Mode. He's basically a combo of Golden Molly, Shadow Jake, and Dilon. He can appear in the big room, in which Jake should call a phone around the building, otherwise he'll attack him. He'll also try to get through the vents. If he's seen pounding on one of the vents, Jake should call the phone in the room to make him run off, otherwise he'll crawl through, hold up for a few seconds, then attack Jake. He can also appear on one of the camera at random, and disable Jake's ability to use the cameras momentarily.

Nightmare at Shea's
The Man activates on Night 2. He's quite a dangerous enemy. He can enter the office through either the middle hall, left vent, or right vent. If he's seen looking in through any of these entrances, Mitch should shut off the lights and keep them off until he goes away. Failing or neglecting to do so will make him attack him, resulting a game over.