Sergeant-at-arms

The Sergeant-at-arms (sometimes nicknamed Sarge) is the gatekeeper and is in command of the Sacred Order of the Harvest Moon. Whether he is an antagonist or an ally to Steve is up to the player. He's seen wearing a brown hooded cloak and possesses facial hair, and is sometimes shown holding a scythe. He speaks telepathically.

History
The Sergeant-at-arms is the first in command of the Sacred Order of the Harvest Moon, also known as The Lodge. He's always seen standing in the front of the Lodge entrance, making sure nobody enters, apart from members or initiates. He convinces the amnesiac Steve Mason to join his order by telling Steve that he has knowledge which Steve desperately needs. In order to join the Lodge, one must acquire an application. After Steve turns in his application to the Sergeant, he gives Steve a task to do each day up until Saturday, calling them "Minor Pranks" in order to persuade Steve to carry them out. Though starting out rather benign, each task gets progressively immoral by the day.

He is also seen during two of the game overs. If Sunday arrives and Steve has not completed his tasks, Sheriff Dwayne will kidnap Steve and bring him to the Sergeant-at-arms, who explains that Steve only had a limited time in Harvest and that he was required to give to the blood drive. He beheads Steve with his scythe and collects Steve's blood in a bucket, thus killing him in the real world and resulting in a game over. Additionally, if the player attacks Mom in the kitchen at any point, after Steve is taken away, the Sergeant-at-arms is seen at the police station, and is the one who pulls the lever that electrocutes Steve, also resulting in a game over.

However, if Steve completes all of the tasks, the Sergeant tells Steve that he will receive the invitation whether he accepts or refuses to become an initiate. Once Steve hands the skull and spinal cord to him, the Sergeant disappears until the very end, where he awaits for Steve, having kept Stephanie alive and in captivity. He then explains to Steve and Stephanie that none of Harvest is real, including himself, and that Harvest was a simulation created by the 'Harvesters' - a group of people who 'breed' serial killers for their own purposes. What happens to him and the program after both endings is unknown.

Previous Life
The Sergeant-at-arms was created to lure Steve into becoming a serial killer. It is unknown if he was used for similar projects or not.

Quotes

 * "I'm starting you on the path of initiation to a very special, very exclusive brotherhood. I am merely the administrator of a test. Whether you view me as an enemy or a friend depends on how well you're prepared to pass."
 * "I did not speak, but my mind touched yours."
 * "You must now enter the Lodge. Initiates find it a hostile place."
 * "Minor pranks, really. Nothing overly difficult. More tests of wit than prowess. But complete them you must if you wish to enter these walls."
 * "Only initiates may enter the Hall of the Order of the Harvest Moon."
 * "You always have a choice, initiate. Which choices you make only matter to you."
 * "The hand that grips the knife that stabs the ones who move amid the crop and harvest the fruit. Again, and again, and again. I believe the technical term is "serial killer"."
 * "I expect nothing. What must unfold will."

Trivia

 * Kevin Obregon portrays the Sergeant-at-arms, but he is voiced by Ryan Wickerham, the same voice actor as Steve.
 * Steve Mason and the Sergeant-at-arms share the same voice actor.
 * In an early UK 1994 ad for Harvester, it was said that the Sergeant-at-Arms had a mutilated face. Describing it as "Grotesquely mutilated. His face is stripped to the bone. Lidless eyes in skeletal sockets. Blood beads and slowly drips off his boney chin.". In the final game, he looks nothing like that, and why they changed it is unknown. Although, it's most likely because it would be too difficult and wouldn't make much sense.
 * The Sergeant-at-arms is one of the three unkillable characters, along with Hank and Baby Sister.