Slender Man

The Slender Man is the titular antagonist of Slender: The Arrival, an expansion of the popular Slender: The Eight Pages.

Information
The Slender Man is a mysterious and malicious creature, resembling a suited lanky businessman with a blank face that haunts the woods and kidnaps people after stalking and silently harassing them. One of these victims is Kate, who collects eight pages in the original Slender game before getting kidnapped and brainwashed by the Slender Man. In The Arrival, Kate's friend Lauren investigates her disappearance, only to get harassed and kidnapped by the Slender Man as well, after learning Kate had been twisted into his mindless proxy "The Chaser".

Abilities and traits
The Slender Man is a very enigmatic being who relentlessly stalks supposedly randomly picked victims. As he never speaks, his personality is unknown, but it is clear collecting pages and escaping his grasp viciously angers him. His motives are also unknown, but he is likely trying to make some type of cult based around himself as he's brainwashed at least two of his victims into mindless servitude.

The Slender Man can teleport, disrupt nearby electronics, brainwash his victims (as aforementioned), and spout tentacles from his backs.