Slender Man

The Slender Man is a strange being who was created on the Something Awful forums by user Eric "Victor Surge" Knudsen.

He is described as being a faceless, demonic entity that wears a black suit and kidnaps children. The Slender Man's physical appearance is that of an abnormally tall humanoid who wears a black suit with a black or red tie and a white undershirt. He wears matching pants, shoes and, in some appearences, black gloves. His entire body seems to be completely white, with his face lacking any discernable features. This horror icon rose to popularity when Parsec Productions created the original Slender: The Eight Pages video game.

Abilities & Traits
As made evident in the Markiplier universe, the Slender Man is a creepy and scary figure, but when facing a stressful situation, he can become nervous and go into denial. The Slender Man does not speak often, due to the obvious lack of means of vocal communication, but he can see through long distances, despite the lack of eyes, as shown in Stop It Slender. The Slender Man is also capable of teleportation, and will use this to his advantage when chasing potential victims.

As shown in The Fall of Slender Man, when the Slender Man does talk, he is shown to speak in an almost awkward manner, speaking with an 'indoor' voice and often stuttering when under pressure. When he is aggravated or in denial, his voice gets rougher and louder in an attempt to prove a point.

Markiplier
Mark and The Slender Man do not share a mutual liking for each other, with the Slender Man seeing Mark as an enemy more so than vice versa. In the majority of his appearances, The Slender Man makes several attempts to kill Mark's player character - almost all attempts succeed. Initially, Mark was not understanding of the Slender Man's capabilities, but eventually came to show true fear later on, which soon died down during later encounters. Similarly to mannequins, The Slender Man is known to stalk Mark and follow him through other games, even those that are completely unrelated in every way.

Despite their differences, Mark has come to call The Slender Man his "buddy" on occasion. This, however, could be interpreted as sarcasm on Mark's part, as he still shows a great disliking for The Slender Man.

A previously-unknown side of the Slender Man is shown in Warfstache Plays: Slender - several journal entries supposedly written by The Slender Man suggest that the Slender Man, though showing an outward hatred for Mark, actually harbors great feelings of adoration, obsession and disturbing love for "Markiplier-senpai", which Wilford Warfstache makes known to the public. Mark is unaware of The Slender Man's feelings towards him, and still sees him as someone to avoid.

Appearances
The Slender Man is often considered one of Markiplier's most common arch-nemesis', appearing in many of Mark's playthroughs. The Slender Man has also been sighted in several different pieces of Markiplier media - different live action performances have seen appearances made by the Slender Man. A well known example is a full sketch comedy skit that details The Slender Man's life as he takes a downturn into becoming a pedophile and heroin addict, revealed in an extensive interview with a reporter named Wilford Warfstache.

The Slender Man has made appearances in the following games/videos:
 * Slender: The Eight Pages
 * Sanatorium
 * Hospice
 * Elementary
 * Mansion
 * Ghetto Booties 5
 * Claustrophobia
 * 7th Street
 * Carnival
 * Prison
 * Slender: The Arrival
 * Evil (Cameo)
 * The Fall of Slender Man
 * Slender Space (as a partial necromorph)
 * Slender: Haunt
 * Slender: The Nine Pages
 * The Slender Man Song
 * SCP Slender Mod
 * Suicide Mouse
 * Slenderman (Original)
 * Slender - The Gaze Of Horror

Trivia

 * The Slender Man is one of the most iconic characters in Mark's channel and is one of his most formidable opponents.
 * It is shown throughout the Slender series that the Slender Man has a habit of mutilating his victims.
 * Throughout the Slender Man's Shadow series, dead bodies can be found strewn about the different maps.
 * In Gaze of Horror, this is made evident by the dozens of mutilated dead bodies hanging from the walls and ceiling of the abandoned asylum that Mark was walking around in.