The Administrator, also referred to as the "Keeper" by the Collective and as "Mr. Slim" by Mary Asher, and commonly known as the Slender Man, is the main antagonist of TribeTwelve. Appearing in many videos throughout the series, it is best described as an abnormally tall figure in a black suit with a pale, featureless face and, occasionally, tentacles sprouting from its back. It is unknown what the Administrator wants, but it appears to be following Noah, and before that, Milo and his mother. Initially, it can be inferred from the Corenthal Letters that the Administrator had been stalking Milo since at least 1995.
After Milo's death, Noah uploaded the contents of the tape from Milo's visit to YouTube, resulting in his discovery of the faceless figure. The Administrator is the leader of the Collective, a hivemind-like group of powerful beings that exist outside of the normal confines of time and space. It can be inferred that the Administrator possesses god-like powers and omnipotency, some of which it bestows upon the Collective.
According to the video My Grandfather Karl, a similar creature known as "Der Großmann", or "The Great/Tall Man", was the subject of a legend in Germany. The creature would kidnap children who ran away into the Black Forest. Karl Maxwell encountered it when it attacked a Nazi soldier. According to Karl, the same creature appears in Noah's videos.
The Administrator tends to have distortive effects on electronic equipment, such as audio and video recording devices. It is unknown if the effect is intentional or natural, though comments by the Observer on Noah's Formspring have suggested the latter. The Administrator also has the ability to teleport at will, creating distortion as it does so. According to Future Noah, the Administrator can shapeshift into other beings--most notably the giant spider seen in Fortunes, DEATHTRAPEXODUS, Sisyphus, and Rendezvous--who was later referred to as "Mongo" in TRIBETWELVE VETERANS DAY SPECIAL.
- Introduction - In Memory of Milo Asher (Hidden in the picture of Milo Asher)
- Submission #1 (In the dark hallway door and in the reflection of the television)
- Submission #2 (After Milo starts running, it is seen walking out from the mangroves when Noah faces the camera back behind him)
- Submission #3 (In the static at the end)
- Submission #4 (At the top of the observation tower and at the top of the foliage before Milo starts running)
- Submission #5 (On the side of the road as Noah drives and outside when Milo films.)
- Submission #6 (In Noah's closet, in the doorways of the house during the odd footage, and outside of the hallway window at the end)
- Tape Analysis (Noah points the Administrator out in each of the Submission videos)
- Night Recording (To the far left of the shot of the pool during the lightning strike)
- The Unboxing (Only as a hidden drawing)
- Box Analysis (At the end of the tape after the person with glasses appears, Multiple times in the photos from the cell phone)
- Unknown Caller (Only tentacles)
- Nature Trail Visit (Appears at the end of a path and on top of the observation tower. It attacks Noah near the end of the video.)
- Secret Parent Interview (Can be seen from a distance, but then vanishes when Noah's mother starts talking about Karl.)
- INTERRUPTION (Seen slowly walking towards the camera before lashing out with tendrils visible at the end of the video.)
- Northern Trip Footage (First seen on the plane Noah is taking to New Jersey terrifying everyone on the plane before suddenly vanishing and everyone, including Noah, forgetting about it. It is also seen briefly by Noah just before meeting the EverymanHYBRID crew.)
- November 11th (Seen outside in the parking lot while Noah is in his car thinking he is going crazy and when the camera was glitching out, showing the image of Administrator and the words of the Boardwalk appearing. It also drags Noah to his realm after the appearance of Firebrand, however, we do not see him.)
- Valentine's Day Livestream (Noah claims to see it and says that he's "wondering where he misplaced his face".)
- Mary Asher Phone Call (Appears in Noah's bedroom, and then later at the end of a hall after Noah looks out his front door.)
- The Order (Appears to the cult members and appears in front of the car to Chris, Alex, and Noah)
- The Live Stream Incident (As Noah/Firebrand goes back to November 11th, 2011, he finds himself entering as Past Noah freaks out. The Administrator rises from the floor and drags Past Noah away to his own realm.)
- DEUS EX MACHINA/Obituary (Appears looking at a sleeping Noah and Firebrand, in which Firebrand gives him the finger, to which it responds by tilting his head in apparent confusion, the only known moment where the Administrator is shown expressing something resembling human emotion. His appearance in Obituary is just a clip of his appearance from DEUS EX MACHINA.)
- Milo's Tape (Seen multiple times stalking and attacking Milo.)
- Fortunes (Appears at the boardwalk as Noah takes a drink, and glides up to the camera via his tentacles before disappearing. It also appears among the hidden frames.)
- DEATHTRAPEXODUS (Seen with a panel of eight plugs in his chest, and at the end it attacks the camera with its tentacles being used as spider legs.)
- Crawlspace (Appears at the boardwalk with, rather than tentacles, many pairs of extra arms sprouting out of its back.)
- Sisyphus (Appears at the boardwalk while Noah is spinning in circles. It was also confirmed in the TRIBETWELVE VETERANS DAY SPECIAL that the giant spider is one of the Administrator's different forms and that it is called "Mongo".)
- Rendezvous (Stalks Noah in his spider form throughout the beginning, appears briefly when Noah is fiddling with his night vision, and attempts to capture Noah alongside the Observer by trapping him in the middle of the boardwalk.)
- Facade (Drops down onto the boardwalk as Mongo and chases Noah through the doorway, appears at the other end of the boardwalk once Noah enters the doorway and grows spider legs before Noah turns off his night vision and it disappears, appears on the far left of the field during the news sequence while Kasha Vine is first speaking, and its arm can be seen all the way on the right while Ned Leman Sr. is being interviewed.)