* ActingForTwo: Adam Rosner, the creator of the series, and actor for Noah Maxwell, plays Milo Asher/[[spoiler:Mr. Scars]] in ''Milo's Tape'', due to Milo's original actor leaving very early in the series. He also played the Observer in a few of the early episodes due to Rikki Dorian Audax being unavailable at the time.
* AdLib:
** Almost the entirety of Severance was a huge improvised scene between Noah Maxwell and [[WebVideo/EverymanHYBRID HABIT]]. Which is pretty awesome given what happened and what was explained during the video.
** Sisyphus Noah's Veterans Day [=YouTube=] livestream from 2017 was entirely improvised based on what people asked and what he was "allowed" to say.
** Noah and Kevin's interactions while playing through the first ''VideoGame/ResidentEvil'' during Facade were ad-libbed by both Adam Rosner and Rikki Dorian Audax.
* AllThereInTheScript: According to WordOfGod, the name of Slender Man's GiantSpider form is Mongo. There is no info of this in the series proper, other than an offhand mention of it from Sisyphus Noah during a livestream (which is unlisted).
* CaliforniaDoubling:
** With the exception of the areas where Noah first teleports into HABIT's realm and where he confronts both him and Jeff on the bridge, most of Bridge to Nowhere was shot at where the creator was living on campus at the University of Miami, Florida, despite the realm itself canonically existing in New Jersey. The aforementioned scenes were shot at or near Rutgers University.
** The room that Noah appears in during the Valentine's Stream, The Live Stream Incident and Case Findings was Adam Rosner's place of residence at the University of Miami. Because driving back to his house would've been overly impractical to film such short scenes, the place is considered to be another room in Noah's (already spacious) house.
* ContentLeak: On October 21st, 2020, former series co-creator Ki Scyne leaked a PDF containing drafts of both Sebastian's and Milo's journals that was open for only a week before access expired. These drafts give many important reveals that never were able to come to light due to the series ending, including Henka Visæ's true identity, the character of Sebastian, the big "event" mentioned by the Collective, and who Scriniarii is.
* CreatorBacklash:
** Adam has expressed his disdain for the early "Submission" entries, due to the poor acting from both himself and Milo's actor, and relying on the [[WebVideo/MarbleHornets Operator Symbol]] for creepiness factor rather than the self-made Severance symbol the series would become known for.
** Milo's actor Ember never particularly enjoyed being part of the series, due to her lack of experience in acting and because of personal conflicts with another person working on the series resulted in her severing ties with everyone involved. She also expressed disdain for the Slenderverse as a whole, wanting the series to be wrapped up as quick as possible and ultimately refused to return to the project after one final day of filming, even ignoring a message asking her to come back.
** WordOfGod states that he regrets making Secret Parent Interview, due to his family's lack of experience in acting.
** Another part of the series that Adam heavily regrets making is the Thanksgiving episodes. Due to difficulties working with Sarah's actress, both halves of the video were an absolute nightmare to film, and it ultimately ended with Adam heavily downplaying the ARG aspect of the series for the rest of Season 1, and wouldn't bring back meaningful fan interaction until SCRINIARII.
** Post-series mortem, several people affiliated with other Slender-series have expressed their regret ever being involved with [=TribeTwelve=], in part due to the revelations of who Adam really was.
*** Evan Jennings noted on Twitter that he hates the crossover videos with WebVideo/EverymanHYBRID filmed for this series, and regrets ever working with Adam.
*** During a Twitch viewing party, Chris Hammerburg and Alex Madden apologized for their involvement with the series when discussing the crossover videos. They notably refused to view any videos from Noah's perspective.
*** Valeria Santiago, creator of WebVideo/StanFrederick, also regrets crossing over with [=TribeTwelve=] during the first and second seasons of her own series. She ended up removing and permanently deleting footage containing an appearance from Noah in Season 3 of his series, as she didn't want to give any further exposure to the series.
* CreatorCameo:
** Dylan Sindelar, one of WebVideo/MLAndersen0's creators, voices the father of a girl who sees Slender Man on the plane during Northern Trip Footage.
** According to Chris from WebVideo/DarkHarvest, Jeff from EMH was one of the many cultists in The Order.
* EnforcedMethodActing: Adam Rosner really was under the influence during the events of The Live Stream Incident, in order to make Noah's drunken attitude and incoherent rambling seem all the more genuine.
* FakeShemp: Mary Asher's character is actually portrayed by three different people all at once. Her voice comes from Marissa of the ''Tulpa Effect'' webseries, her body appearance in Milo's Tape is that of the creator's mother, and her picture in the Obituary newspaper is actually a mugshot of the late Mindy [=McCready=].
* HeAlsoDid: Series creator Adam Rosner is also the VFX artist of the horror comedy movie ''Lillith'', which he worked on alongside several well-known Slenderverse creators including WebVideo/StanFrederick creator Valeria Santiago, Vincent Caffarello from WebVideo/EverymanHYBRID, Chris Hammerburg from the WebVideo/DarkHarvest crew, and Lee Esposito of WebVideo/WhisperedFaith fame.
* LongRunners: Of all the other Slender Man webseries out there, [=TribeTwelve=] is possibly one of, if not ''the'' longest running of them all. To put in perspective: WebVideo/MarbleHornets started in 2009, and ended in 2014. WebVideo/EverymanHYBRID started in 2010, and ended at the beginning of 2019. That left this series as the only one of the "big three" Slender Man projects that was still ongoing since 2010, until it's premature finish in 2020.
* OrphanedReference: Severance contains one for WebVideo/MLAndersen0 of all things. Right as HABIT is wrapping up his lesson on the titular symbol with Noah, Michael Andersen appears in the former's bathroom, coughing profusely and with a large stab wound in his side. This was supposed to foreshadow a video where HABIT tortures Michael in a bathtub, but the video was never uploaded by MLA creator Dylan Sindelar (who lost the footage), resulting in the scene becoming a BigLippedAlligatorMoment. Hell, due to Michael's face being obscured in the video, fans weren't even sure if the man in the bathroom was actually Michael until Adam indirectly confirmed his identity to be "[[FunWithAcronyms Chairman Needles]]".
* TheOtherDarrin: The Slender Man seen in The Order was not portrayed by this series or WebVideo/DarkHarvest's actors, but was instead filled in by Daniel of EMH, who was portraying the character for his home series at the time.
* RealLifeRelative: Karl Maxwell's actor is Adam's real-life grandfather whose mothertongue is German. Noah's parents, seen in Secret Parent Interview, are also his actual parents.
* RoleEndingMisdemeanor: Or in this case, ''series-ending'' misdemeanor. After it was exposed that he had groomed multiple underage girls over the internet, sexually assaulted at least one female friend, and was a pretty unpleasant individual to be around in general, Adam Rosner immediately terminated any and all social media accounts he was still active on, going to great lengths to hide from the consequences, as the majority of his former friends and collaborators from the Slenderverse condemned him for his actions. A month after the truth came out, the series puzzlemaster, Scyne, made it adamant on Reddit that Adam has zero plans to continue [=TribeTwelve=], due to focusing on his personal life and because of his tarnished image.
* StaffCreatedFanWork: Adam Rosner, creator and star of ''Tribe Twelve'', also made ''There's A Monster In My Closet'', which parodies his own series and other similar web-series, right down to ''Tribe Twelve'''s protagonist, Noah Maxwell.
* StockFootage: One of the scenes from the news sequence is the same footage filmed for Milo's Funeral reused.
* TechnologyMarchesOn: As with most projects associated with Franchise/TheSlenderManMythos, many of [=TribeTwelve=]'s early entries show just how long the series has been running. The best examples include Noah's dated TV and flip-up cell phone from Season 1 (which he eventually swaps out modern ones by the time Obituary is uploaded).
* ThrowItIn:
** During Noah's interrupted livestream, he calls himself "Adam" (the creator's real name). When people in the stream notice, he explains that he's been calling the cops about disturbances so much he's had to start using fake names to get them to respond. Also, according to WordOfGod in the Media Meltdown video, the knocking itself is unscripted: a friend who lived nearby was watching the livestream and decided to play a practical joke.
** Apparently Rikki Audax just decided that he wanted to smoke during the filming of DEATHTRAPEXODUS, which was kept in the video.
** The random group of people that appear in Rendezvous weren't scripted, they merely showed up during filming. The creator decided to make the best out of this by making Noah film some sentient mangroves before they suddenly appeared.
** The Observer's appearance at a bench near the water was completely unintentional, but fit in so well that the creator decided to include it.
* TroubledProduction:
** Milo's former actor left the series very early on, leaving any appearances from the character to be either documented in archive footage. Milo's appearances both within his journal (both figuratively and [[SoulJar literally]]) and in Milo's Tape were actually Adam Rosner portraying him.
** From Bridge to Nowhere onwards, the progression of the series has severely slowed down due to Adam's commitment to finishing medical school.
** As of 2020, production on the series has flat-out ceased after Adam's predatory and abusive behavior towards minors became known to the public, resulting in everyone else involved with the project pulling out as well.
* WhatCouldHaveBeen:
** Bridge to Nowhere was originally going to be a very short video, with Noah simply finding the bridge he encounters HABIT on the moment he teleports from the bathroom into the old building. The creator was ultimately unsatisfied with this, and decided to add in the scenes where Firebrand texts Noah and where Noah explores the areas within HABIT's spirit world.
** There were originally going to be scenes filmed that expanded upon Milo's early life, but unfortunately couldn't happen due to Milo's actor leaving the project and refusing to return. Instead, these scenes were touched upon in Milo's journal.
** Sisyphus Noah was originally going to host his 2017 Veteran's Day livestream at the Boardwalk, but instead does it in the laundry room in his house. WordOfGod says this was due to the lighting at the Boardwalk being unfavorable for "the dark times" during the day, and that the bugs would make it impossible to film at night.
** Noah was initially going to meet his Rendezvous future self at a picnic table in front of the Nature Trail tower (as shown [[https://tribetwelve.wikia.com/wiki/Fortunes?file=Fortunes_12606.jpg here]] and [[https://tribetwelve.wikia.com/wiki/Fortunes?file=Fortunes_20396.jpg here]]), but the scene ultimately proved to be impossible to film due to poor lighting conditions, and because of damage to the area caused by Hurricane Irma.
** The scene where Noah leaves his cloth wrapping on a tree and replaces it with a band-aid Firebrand give him was initially going to be in Facade, but was moved up after the creator forgot to wrap his hand during the meeting with Future Noah.
** An entire video arc that the creator made up during his college years ended up getting shelved due to the arc being mostly filler content.
** The series was initially going to be finished sometime during 2018, but had to be put off due to the creator attending medical school for most of the year.
** As of 2020, the ''entire series'' can be seen as this. Although Adam had made it adamant that he had an vision for how the series would ultimately end, the chances of it ever coming to fruition are slim to none due to the truth about his behavior coming out and with most of his fellow creators (and the fanbase) turning their backs to the series.
* WordOfGod:
%%** Lots of this in these interviews [[http://blip.tv/MediaMeltdown/media-meltdown-interviews-tribe-twelve-5814627 Media Meltdown Interview]].
** The 11/11/12 livestream was supposed to [[spoiler:play the INTERCEPTION video at 11:15PM, but due to technical difficulties that didn't happen. The video was then supposed to play when Noah was off-camera, but due to an error on the Livestream's side only the audio of the video played. WordOfGod has declared he'll use a different Livestream host from now on).]]
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