Since I'm seeing some people talk about the Rooster Teeth Shane letter stuff, I thought I'd give a quick overview of it from someone who's been in the RWBY fandom since before the letter broke. Apologies that this is a bit long.
The letter was written by Shane Newville, an apprentice animator to Monty. Shane didn't have a great childhood and animation became one of his methods of getting through the day, especially after being diagnosed with some mental health disorders. Shane met Monty and the two hit it off like wildfire, with Shane following Monty into Rooster Teeth when Monty was hired by them around Red vs Blue's 8th season. Shane, along with most of the animation team that worked on RVB's CG fights from season 8-10, left that team with Monty after he announced that he wanted to make his own original show, that being RWBY. Something worth noting about Shane is that he didn't so much like Monty as adore him- in the letter, Shane writes of Monty like a messiah and keeps taking shots at all the other animators for not coming close to Monty's conviction or talent and being unimportant to Monty's wider "vision."
Despite some promising early trailers (Shane worked on two of them, the Black and Yellow trailers), RWBY's first two seasons are seen as very clunky and flawed in a lot of areas- Volume 1 was made by about thirteen people and didn't even have enough budget to make background characters, so instead it relied on shadow people. The animation was very finnicky outside of the combat, which Monty made shine. What kept people interested in RWBY beyond the fights was a sense of genuine charm to it, between what was seen as very good character design and some interesting takes on fairytales for character inspiration, as such RWBY gained a very passionate fandom in the early days who were inspired to write fansongs, cosplay as the characters and even create costumes for their OCs- a character in-show, Neo, was inspired by Monty seeing a female cosplayer's take on the character Roman Torchwick.
Something I should note here- Monty adored working with Rooster Teeth and didn't regret it for a second, Shane's claims that Monty wanted to leave RT and take RWBY as a franchise with him have never been supported by an alternate source and I'm inclined to think he was lying or misconstrued something Monty said before his death.
Monty's death proved to be a disaster for Shane's mental health- as mentioned, he has a long history with mental health issues and after Monty died and the choice was made to keep RWBY going, Shane went overboard in trying to emulate Monty's machine-like work ethic of long nights. The problem was that Monty was one of a kind and trying to replicate his casual attitude of working through the night just wasn't possible, and Shane's marriage with his wife Katie fell apart soon after. The other big problem for Shane was that the software he and Monty were used to, Poser, was an old and outdated piece of shit software. All the new members of the crew had to be trained to use Poser and it made production a nightmare, especially when Volume 3 was set to push the tech to its absolute limits, causing frequent crashes. Poser proved such a problem that Volume 3's finale was only finished and ready to air hours before its airdate. Monty only used Poser for so long because it made animation rigging easier so he could reuse combat animation, and various Rooster Teeth employees have noted that it was a piece of shit tech that Monty made dance. As such, Rooster Teeth made the executive call that from Volume 4 onwards that the show would use Autodesk Maya, a more user-friendly software that's one of the standard bits of software animators are trained in and would cause less production issues than Poser.
Shane wasn't happy with this call, and saw the choice as a betrayal of Monty's work ethic (fun fact, Monty's literal last tweet before his death showed that he was getting practice in on Maya indicating that he was fine with the choice to shift). In fact, Shane saw anything that deviated from how Monty would have done it as a betrayal of his friend, even when it was done to make production easier in the long run. Be it having Monty's wife audition for a character like anyone else, cutting out plot beats that would have made no sense or would have been actively detrimental in the long run, Shane frequently butted heads with the writers and directors for going against "Monty's vision." As such, through the lens of Shane's mind, which was already falling apart due to his best friend dying and his wife leaving him, Shane saw the situation as him and Monty's wife being the true protectors of RWBY as a franchise and Rooster Teeth being the "soulless corporation" that was stealing Monty's vision and not sticking to the letter of the loose plans Monty had left lying around about where he wanted the show to go (ignoring that Monty himself was prone to just adding things during the show for the hell of it, including
an entire magic system just because he thought it would be cool, and he brought Miles and Kerry in specifically because by Oum's own admission he was a terrible writer and wanted their help). Shane's complaints about the story omissions in particular feel like him being angry that Miles and Kerry engaged in the practice of... editing a script.
Eventually, Shane was let go from Rooster Teeth after Volume 3 wrapped, likely in part due to his own refusal to let the matter rest and his own inexperience with Maya. He wrote the big old letter alleging that RT were "defiling Monty's vision" or some such, and barring some cut content from Volume 3 that has since been leaked (such as Monty working on a fight between two characters when last year the animation for that test footage was leaked), nothing in Shane's letter has ever been verified except by ex-Rooster Teeth employees who already had a grudge to bear with the company, and even then some of those employees have since retracted their support.
Really the whole thing is more tragic than anyone else- Shane lost a very close friend who helped him get a dream job, his life fell apart shortly after and in his attempts to try and keep things as they were which was simply not possible after Monty's passing, he just alienated his own coworkers and wound up losing his job as a result. Likely everything in the letter is true... from the perspective of a man going through severe depression and jumping at shadows.
Either way, the fandom as a whole doesn't like to talk about the letter, especially since several Youtubers use the letter every chance they get to insult RT and claim that it's gospel (they're not even very good critics, anyone could write them under the table). One such imbecile, MuffinManDan, even went as far as to consider on Discord hacking Rooster Teeth's servers to find evidence that the letter's contents were true, which would have landed him with corporate espionage charges if he did. Ironic that Shane derided Rooster Teeth for, in his eyes, becoming opportunistic vultures about RWBY when people who claim to support Shane would themselves become vultures pecking at RT.
For the record, RT themselves have never officially responded to the letter save for one admin for the site that offered his own perspective on the letter. They have a tendency to just stick their heads in the sand whenever controversy flares up and it seems to work out for them.
tldr: Shane was going through some very rough times and the letter was his only outlet, but it shouldn't be taken as gospel about what really happened behind the scenes after Monty died, especially since Shane himself and Monty's wife don't like to to talk about it and BTS evidence indicates that Shane was getting angry over other people doing their jobs or streamlining a production timeline.
Oh BTW the whole thing of "Monty's wife killed him" is a completely exceptional conspiracy theory that even those aforementioned vultures have disavowed, this is basically the only site that believes it wholesale.
