Kyle in Post-Halloween Footage'
Kyle is a friend of David's. He first appears in Halloween Footage Part 2, when David spends the night at his house on Halloween to attempt to go trick-or-treating, but to no avail, as Kyle apparently runs off at some point and is found later, exhausted.
The next day, they head to an abandoned dock. David apparently catches a glimpse of the Slender Man and runs off, just for Kyle to catch up with him.
Kyle later appears in A Strange Voicemail, sitting on the computer and hanging out with David.
Kyle is mentioned in the video December, as David states he has not seen or heard from Kyle since the Halloween videos.