Brian & Tim Interactions and Parallels
The Brian-Tim relationship is one that's really interesting to attempt to analyze because it's so thoroughly shrouded in memory loss, lies, and mystery that it's difficult to figure out what kind of relationship they really had with each other during the course of the series.
The Season One relationship is notable in that Brian is conspicuously absent from any on-screen footage. Even in the old tapes from college that Jay is reviewing and uploading, Brian is frequently absent from project meetings even when they're being held in his house -- characters ask where he is and no one is especially sure. That alone is an interesting parallel with his presence -- more specifically, his lack thereof -- in the season as a current day whole. A possible explanation for this could be found in the 'Advocate' upload to the totheark YouTube Channel -- if you interpret this video as a warning or cry for help on Brian's behalf, and the subsequent Entry #16 upload that immediately follows it as evidence that someone was shot and injured in Brian's house, then it's arguable that Brian was injured fairly early in the season and wasn't able to be an active participant in the series. Because Brian was injured, Tim had to pick up the slack and work as the 'face' of totheark -- arguably something that was a deviation from their usual dynamic, given that in the footage seen uploaded as Season Two, Brian is either the 'face' of the series on his own, or is present alongside Tim on screen. Arguably, that could be due to the fact that Tim was the one who was injured early on in this season, but the fact that Brian remains a comfortable front facing figure for the channel in Season Three even after he and Tim have separated seems to speak to the idea that Brian is the more comfortable of the two being an active representation for the partnership than Tim is.
Season Two is much more difficult to get an accurate read on, due to the mixed timeline of the majority of Marble Hornets footage being filmed in 2010, but not being uploaded until much later in 2011, and the totheark uploads responding to the old footage in 2011, using footage filmed in an ambiguous time frame (for example, the Extraction upload -- did totheark have this footage of Tim walking lying around as a kind of b-roll that made it possible for them to use his visage without Tim being an active partner anymore? Or is it possible that Tim was still around to work with totheark by this point in 2011?). It's borderline impossible to figure out exactly when events take place, and what state Brian and Tim's relationship was in at any given point.
That said, it seems to be that they spend a roughly equal amount of time on their own and with each other on the footage from this season. Brian appears on his own a couple of times in the background of footage (for example, Entry #39 when Brian films Jay sleeping in his car at night, and Entries #40-41 when he hovers in the background of Jay's shot and goes to retrieve his camera after he drops it), and Tim appears to act on his own a couple of times (such as in Entry # , when he gets his leg broken and Entry #52 when he seems to wrestle the gun away from Alex on his own), and the two of them seem to spend an equal amount of time acting together (such as in Entry #45 when they lure Alex out of his house to attack him at night and in the Entry #76 footage from Season Two of them getting Jessica out of the motel). Before they seem to have been separated after Brian's final fight with Alex and Tim's apparent encounter with the Operator in that Entry #76 footage, they were evidently working very closely together and were both able to pull equal weight in their machinations as they worked together towards their shared goals. Season Two is most easily read as an equal partnership between the two of them.
Season Three, on the other hand, seems to show Brian and Tim pretty firmly separated. Like Jay in Season Two, Tim seems to have lost all relevant memory of the last handfulf of years and is no longer an active participant in the totheark partnership. Brian doesn't seem overtly concerned about this separation, as in: there doesn't seem to be any overt attempts on his end to get Tim reinvolved in the mess. It's possible that Brian was simply waiting in hopes that Tim might regain some memory after his encounters with Jay and return on his own to his and Brian's partnership, but given the amount of time that passes during their separation, this seems somewhat unlikely to me. Instead, given that almost a full year elapses between their separation in January 2011 and Jay's first interaction with Tim (give or take a few months depending on whether you'd consider Jay's first distant filming of Tim in Entry #52 or Jay's first conversation with Tim in Entry #53 to be the more significant interaction here), it could be argued that Brian is, in some way, almost relieved for Tim? If that makes sense.
Here's what I mean: Although Brian is almost entirely consumed with his need to get revenge on Alex, it's still pretty obvious that the majority of his anger stems from the perceived Harm he blames Alex for causing. Before the revelation of Tim's medical history, Brian blamed Alex not only for attacking the rest of the cast in college but also for being the source of the Operator in the first place, opening the door for harm that affected everyone. The fact that Tim, in a way, was able to 'escape' both the memory of the trauma and the source that exacerbates it (Given that, due to Tim's "I was doing fine; I was getting better" speech, it's safe to assume the Operator had largely left Tim alone during that year), makes me think that perhaps Brian was reluctant to shatter that presumed safety. Bringing Tim back into the fold at this point wouldn't serve any positive purpose, rather, it would make Brian an overt source of harm in Tim's life that could make him alarmingly similar to Alex, whom Brian resents. I think it makes the most sense for Brian to have sacrificed the totheark partnership for the sake of Tim's recovery (further cemented to me by the interaction Brian has with Skully in the ark -- him finally being willing to let go of his desire to utterly destroy Alex only in the wake of the assurance that Tim is still alive).
And I think the 'sacrifice' of that relationship is a major factor of what makes the revelation of Tim's medical history something that strikes Brian so deeply. Not only is Brian's deepset perception of Alex destabilized (Brian has spent years by this point holding onto, feeding, and seeking to justify his hatred of Alex as not only a perpetrator of assaults but as the source of the Operator -- Brian saw Alex as The Villain, the One person who not only hastened the Operator's destructions of everyone's lives, but also the one who Led the Operator straight to them in the first place. The revelation that Alex is, essentially, just another victim in the mess is as terrifying as it would be aggravating), but also as a pointed betrayal by Tim himself. Tim and Brian worked together for years to take revenge on Alex, when the whole time, Tim was sitting on the information that it was all his 'fault' to begin with, making all of their combined efforts something of a farce or a joke.
That said, it's fascinating how Brian can't seem to stop himself from caring about Tim. Certainly there are numerous arguments to be made about the real harm Brian did cause to Tim -- most notably the theft of Tim's rescue medication in Entry #61 that leads to a seizure; it's not something you can dismiss out of turn, but it's also not like, incredibly out of place in the series? In the sense that the entire series is ultimately about the incredible harm every single main character does to each other and themselves. That's just to say that Brian is not a unique source of harm in this series, and the often warped dynamics Brian and Tim share are equal among every other dynamic we see portrayed (yes, even Tim and Jay).
Here's what I mean: Even after Brian finds out about Tim's medical history, and steals medication Tim could have used to diminish the effects of a seizure (I think I have seen some people describe the events of Entry #61 as Brian 'deliberately Triggering a seizure', but this is not the case. From a Doyalist standpoint, it feels obvious to us to correlate the theft of the medication to Tim's seizure because they take place at the same time and the creators planned them to take place in the same single take, but from a Watsonian standpoint, it doesn't make any sense that Brian would have known that Tim would have a seizure almost immediately after Brian stole a medication he could have used to prevent/alleviate the effects of it -- textually, this is just a coincidence), Brian responds to Jay uploading Entry #64 with the 'Display' upload, which takes a thoroughly accusatory tone when it says "YOU ABANDONED HIM; I SAW".
It's almost kind of funny, the way Brian almost seems to flex on Jay sometimes? With this upload in particular, it always reads to me as Brian saying "You left him behind, I watched you do it, but I would never do that to him". It feels especially pointed at this point because on Twitter Jay makes it clear that that upload was posted long before Jay was able to get back into contact with Tim. Jay comments on the upload on the 31st of October and admits that he hasn't heard from Tim and is still trying to work up the courage just to go look for him, and the subsequent upload of Entry #65 of Tim's footage from that day isn't posted for another two weeks after that. And in a way, this reading of Brian's intent is almost Affirmed by the uncovering of Brian's footage from that day -- Tim was left behind, and Brian is the one who goes out and finds him and hides him to make sure that Alex (who was also skulking around the area that day) wouldn't be able to get to him while he was still recovering.
Similarly, although Brian does continue to steal medication from Tim since it isn't something he's able to get on his own, I do find it somewhat significant that Brian essentially contiues to let Tim know that he's doing this -- almost as if he's compensating for the first time when Tim went in search of medication that had already been stolen. I also think the rest of the Entry #73 footage is more significant -- Brian choosing not only to upload footage of himself breaking into Tim's house, but also to deliberately post it to the main Marble Hornets channel where Jay/Tim are likely to see it almost immediately (considering that sometimes days would pass before Jay noticed/commented on a totheark upload) in order to warn them both that Alex was skulking around Tim's house. It's also significant that Brian doesn't wait this out or passively observe whatever plan Jay and Tim might have come up with to handle this -- almost a week passes before Tim comments on the Entry's upload because he's been distracted taking care of Jay, who was catatonic at the time; it's possible that Brian wasn't at all willing to let them be caught unaware and broke back in to take care of Alex himself before they had a chance to come back.
Regarding their final confrontation in Entry #83 -- for one, I do not think that Brian is responsible for the display of Jay's body in Tim's house nor the writing on the mirror that reads 'YOUR FAULT'. I don't know if I can say for sure who I do think would be responsible, but 1) I fail to see why Brian would go through the effort of creating this display when there's no way he has access to Jay's corpse to use as a centerpiece, so I'm not sure what the point of the mess would have been without Jay there as a very pointed detail of it all and 2) when Brian stumbles into the scene after Tim does, he seems to be just as caught off guard as Tim was -- hesitating as he takes it in and startling pretty badly when Tim turns on him, implying a level of distraction that I don't think would be present if Brian knew what he was about to walk into. Not to mention that, given the Quandrant upload released before Jay was killed, I don't think it makes sense for Brian to believe it was in any way Tim's fault that Jay died -- even if Brian had successfully warned them off with that upload, Brian was also the one who led Jay back into the area despite Tim's attempts to keep him out of it; despite his confusing motives and the avoidance of straightforward communication, Brian is a pretty consistent character throughout the series and has never been shown to arbitrarily lay blame at people's feet -- I don't think it makes sense for Brian to believe let alone deliberately imply that Tim was somehow responsible for Jay's death, so I don't think this display had anything to do with him at all. This is just reaffirmed to me by the alteration of the mirror to read "LAST CHANCE" when Tim goes back to his house after Brian has died -- although they were both being teleported all over the place during that confrontation, I fail to notice a coherent absence where Brian could have had the time to clean the mirror to change the words before his death, so someone/something else has to have been responsible for all of that.
Additionally, I believe I've seen some people describe Brian's offer of Tim's mask in this Entry as a way to back Tim into a corner -- threatening to withhold something (like his medication) from Tim unless he agrees to return to being "Brian's dog". For one thing, Season Two makes it pretty clear (to me, at least, I suppose) that totheark was an equal partnership, and Season One seems to make it even more explicit that Tim is an active and willing participant in the partnership due solely to how frequently Tim makes moves entirely on his own; it's not as if Brian is breathing down his neck the entire time giving him direct orders or forcing him to do specific tasks. Second, while it is true that Brian seems passively willing to let Tim walk off into the night in some kind of dissociative haze in Entry #61, as I've already said, it doesn't make sense for this to have been a deliberately triggered event Brian caused on purpose given that he didn't do anything to induce a seizure in Tim, so much as he just withheld any assistance once it had already coincidentally started -- meaning it doesn't make sense for this incident to be read as Brian forcing Tim to behave in certain ways or using Tim as a weapon to attack Jay. Brian is in Rosswood that night, but we're not given any indication that he interfaced with Tim before Jay found him. Whatever Tim's relationship with his mask is, it's not as if we see him drop it during the Entry #76 footage where he and Brian presumably separated after Season Two -- it's not a requirement for Brian to have given it to him that night, he's just as likely to have already had it somewhere in his home.
Brian offering the mask to Tim in Entry #83 doesn't read as a threat to me, it reads as a last-ditch effort on Brian's end to attempt to reignite their Partnership. The tone of the last totheark upload 'Null' reads as remarkably defeated, like Brian has already accepted that he's going to die soon and probably won't be able to achieve his goal (maybe even finally stopping to reflect on whether any of it was worth it at all; Brian always intended to use Jay as a means to an end -- hoping Jay would lead him to Alex -- but I don't think Jay's death was anywhere on Brian's radar of 'acceptable outcomes'). Brian already knows where the story is building to, he already knows how his story in particular is going to end, and I think the offer of the mask is a genuine question on Brian's part -- "Do you want to help me stop Alex before this can go any further?", or maybe even "Don't you want revenge on him now too?". But I think it's a question he already knows the answer to, which is ultimately what leads him to just, let go of the ledge, as opposed to waiting to see if Tim would be willing to follow through with pushing him off. We're not sure what Tim would have done if Brian hadn't let go, and it's almost like Brian wasn't willing to let either of them figure out the answer -- Brian doesn't have to know if Tim would have been willing to kill him, and - if he had been willing to kill - Tim doesn't have to deal with the guilt of killing someone who would have turned out to be his once best friend from college. Brian sparing Tim one more time, just to, as I mentioned earlier, go on to be willing to let go of the hatred Brian had held onto for nearly a decade after being reassured of Tim's continued survival.
Now, Tim's perception of his and Brian's partnership is somewhat more difficult to pin down. Although I do believe that Tim was an equal partner in the totheark dynamic, it is difficult to piece together what the specific nature of his participation truly is. There are a couple of options that most people tend to rely on - 1) Plenty of people consider Tim to be a completely non (or at least Dubiously) consenting party in the relationship, percieving Tim's masked state as some kind of fugue or dissociative state that Brian deliberately triggers in order to make Tim easier to control -- this doesn't make much sense to me. For one, although it could arguably be applicable in the Entry #61 incident, the theory seems to fall apart when it comes to more complex actions Tim has taken on his own -- such as breaking into Jay's house to watch him in Season one or intervening to prevent Alex from killing Jay/Jessica in Season Two. Those two incidents in particular showcase an awareness of his surroundings, a patience that doesn't seem consistent with someone mindlessly following specific orders while in a dissociative state, and an independence of action that doesn't seem likely to be induced by someone standing directly behind his shoulders, telling him what to do.
Another common interpretation of events is that Tim has Dissociative Identity Disorder -- Tim's masked state is that of an Alter who fronts in order to work with totheark and is a willing participant, while Tim is unaware of his involvement. This is definitely more cogent to me, Tim's traumatic past (more to do with the psychiatric inpatient system than the Operator somehow inducing this in him) does lend him to the kind of background that tends to lead to DID. Some people do bring the "Brian is manipulating Tim into following orders" reading into this potential, but I don't think changing the name of the disorder makes this any more likely to me. Instead, I think it could make sense that Brian is aware of Tim's disorder only in that he can differentiate between the Alter he shares a partnership with and Tim, who would be unaware of it, and doesn't force Tim to participate when he's the one fronting (hence, perhaps, the length of time Brian was content to work on his own before Jay got Tim involved anyway in Season Three; and the reason why Tim says he hasn't heard from Brian in a while in the Entry #15 interview with Jay -- Brian can tell when Tim is fronting, and keeps his distance in order to spare Tim the stress of involving himself in the hunt for Alex).
Another potential is that Tim is working on a wavelength similar to Jay in Season Two -- Tim was a conscious, willing participant in the totheark partnership as himself, but after his encounter with the Operator before the events of Season Three, he lost all of the relevant memories and wasn't able to pick up the thread until Jay pushed him back into it. Under this reading, it's likely that Tim was simply lying in the Entry #15 interview with Jay when he claims to not have heard from Brian in a while (it is a little funny how in the "everyone is lying" series, a lot of fans are completely content to take characters' claims at face value and presume they're telling the truth before considering lies as a possibility lol). This is a thoroughly cogent reading, but it does tend to make moments like Entry #61 and even the part of Entry #67 where Tim attacks Jay and Alex respectively somewhat unexplained by the theory itself.
However, it's not as though we don't have well-established precedent of the Operator's influence inducing violent outbursts in characters not typically predisposed to behaving that way -- such as Jay attacking Tim in Entry #77 despite the reveal from Jay's unpublished footage released as Entry #82 that Jay had apologized and intended to meet up with Tim to work alongside him again, before that decision is somehow altered by his encounter with the Operator that night. Arguably, Alex's actions taken in college could also be explained by this intervention by the Operator -- after all, despite being prone to monologues and explanations in late Season Two and throughout Season Three, Alex notably never speaks during the assaults we see him perpetrate against Brian, Tim, or Jay in the footage from the college era encounters (But enough about that here). Tim is not necessarily unique in this effect of the Operator's influence -- if you do subscribe to the Third interpretation of Tim's actions (essentially that in every other season he was acting cogently as Himself), then there would only be two instances of Tim falling victim to this influence, and that's not exactly a stunning exponential increase in comparison to other characters.
Now, prior to the events of the series -- during the college years -- their relationship was a lot more clearly defined. Tim describes Brian as his "first" friend, and the short clips of those years that we get really seem to imply that Brian was the one who opened the door for Tim to make friends with the rest of the cast. The way Tim behaves in his first interaction with Alex, during the Audition tapes we see uploaded as Entry #84, Tim is recalcitrant and reluctant to engage with Alex at all before Brian encourages him to go ahead. In later tapes, though, we see Tim comfortably bantering with all sorts of characters: Sarah, Jay, Alex, and Brian. Brian was not only Tim's first friend, but also the first point of contact he had in a number of friendships he had in college in a way that makes it all the more devastating that The Operator's influence in their lives took a sledgehammer to all those relationships, leaving Tim all on his own.