I don't think she's been established to be able to do that either, but we'll have to work out exactly what "it" was first. The best I can figure, if sticking with abilities we know the antagonists have, is they jumped the PC into a different timeline that split off from the current one long enough ago for Fozzer to have absorbed different propaganda. If it wasn't that, then it read more like a Mind or Heart power to change his mind that way.
Spoiler I always figured it was pretty explicit by this point that troll society, especially post-scratch/on Alternia, was being manipulated by Doc Scratch via his agents in such a way to eventually give rise to the conditions necessary for Lord English to come into being, which necessarily entails 12 trolls playing and winning SGRUB [to make the universe with the kids, to make lil cal and AR, to eventually create the green sun, all of which are retroactively necessary to make Doc Scratch and Lord English]. That's like, Doc Scratch's whole motivation, being an excellent host [for lord english], with the Various Female Underlings (ie snowman, The Condesce, and The Handmaid) just being manipulated pawns for that end. Hence like, breeding an entire population of dogmatically authoritarian, aggressive, bloodthirsty teens who are taught from an early age to build really vertically tall weird buildings and worship the literal time traveling demons their whole culture is being manipulated by, especially given how the Beforan trolls' ostensibly benevolent and comparatively peaceful culture made them really poorly suited for playing SGRUB. Doc Scratch and by extension Lord English have a vested interest in keeping Alternia as a horrific pressure cooker of a society that spits out little SGRUB winners, so if there's any time fuckery going on that explicitly seems to affect anti-Hemospectrum elements, I'd be pretty highly suspicious of it being part of the above.
Spoiler In regards to Marvus being a limeblood, I hope not. An ostensibly benevolent Purpleblood using his chucklevoodoo powers for something other than being weird clown secrete police is way more compelling to me than him being like, a secret member of a caste with no real lore beyond "they all got killed for mysterious cool powers".
Spoiler But he's NOT using them benevolently, he's using them to kill off entire audiences just so he's not inconvenienced.
Also, yes, we know it's likely Doc Scratch, but how specifically did he do it? Spoiler Timeline fuckery doesn't usually work in such a way that it can change a single person's outlook on life to the exact opposite of what it previously was and apparently change nothing else at all. That reads more like a Mind or Heart power than a Time one.
Spoiler Ostensibly for the purpose of breaking down the hemocaste system, hence the whole "Shaking things up would actively help disprove the validity of the hemospectrum because purplebloods are tangibly stronger than seadwellers" speech. It's also pretty well established that every mass event with trolls eventually descends into a bloodbath via Wanshi (among others, keep in mind FLARPing is both very popular and ostensibly a bloodsport), so I'm not really sure if I buy the spontaneous murder is a product of him and not just like, trolls being aggressive socipathic murder machines by virtue of their upbringing. Regardless, I'll take a woke-ish purpleblood over a limeblood. I'd find any of these trolls being a limeblood to be a hella asspull by this point in the plot.
Spoiler That just speaks to Bronya being remarkably progressive, not Karako being particularly interesting or compelling. Among the friendsims, I found him to probably be the most flat and least interesting. Oh cool, cut-rate Karkat with no actual dialogue.
Spoiler I'm pretty certain Karako's spoiler-heavy so they're limited in what they can say yet, and also he's nothing like Karkat. Karkat was raised by a lusus, not a jadeblood, Karako is not a mutant, and Karako doesn't put on a show of being angry while being caring, he's happy most of the time and then snaps when someone insults his lusus. As for Marvus, if he has the power to work up a crowd that much and he isn't actually either not as nice as he seems or up to something, why doesn't he use that power to STOP the bloodbath? Also, how does another bloodbath in a culture built entirely on them do ANYTHING to destabilise said culture?
And I'd hardly say it's an asspull when it was already confirmed way back that Hiveswap would be releasing more limeblood lore.
Spoiler I meant more in the "Nondescriptly dressed troll with a weird lusus situation (Karkat only has one by virtue of the sufferer's followers working in the shadows with the implication that a normal lusus would reject hin) who is at least somewhat ornery" Like I said, I don't buy that the crowd being worked up was a Marvus thing rather than a "trolls being violent in large groups" thing, and I think that actively using his powers to prevent the normal (and ostensibly holy given the beliefs of the clown religion we've seen thus far) mass killing of lowerbloods would be a pretty big giveaway that he's engaging in active sedition, which is explicitly a thing people get killed over. Insofar as Marvus not actually do anything to destabilize the culture, he like, explicitly explains this. Showing off how powerful Purplebloods are in order to invalidate the hemospectrum and spreading enough chaos to make it impossible for the system to function as intended.
Limeblood lore =/= Btw this minor character from a spinoff game is actually secretly a member of the previously unseen dead caste that has super speshul powers Like, that could be the case, but I'd consider that canon sue levels of bad writing
Regardless, a lot of this just comes down to personal taste. Spoiler I find the limeblood thing most interesting as a piece of ancient lore and not a suddenly plot relevant thing that still exists, and I find Marvus to be both significantly more benevolent than the majority of purplebloods we've been shown, and significantly more interesting than the alternatives.
Even if that theory doesn't pan out, I still think Marvus is likely Spoiler a Mind player. -He has a lot of knowledge and a lot of dramatic flair, both of which we've seen in Mind-ers before. -The Extended Zodiac says that the Mind-bound can "execute a plan with flawless grace and precision" and "change [their identity] from day-to-day", and he's certainly concealing things about his identity; even if he's not hiding his blood, the text describes him as "of modest height" and "lanky" in contrast to his appearance in the picture and the PC can easily drag him around, so I think he's using psychic powers to make people see him differently from how he actually looks. -His use of a sword-cane could be a Terezi callback. -His route has parallels with Boldir, who's Heart, the opposing aspect, and Heart is also the aspect I and a lot of others guessed for Ardata, so there's some nice symmetry there. Specifically, in the sudden death route the PC just decides not to meet them, in the successful route they perform a deception together, and in the unsuccessful route they become friends anyway but the timeline collapses around them. -Also, he has parallels with Chixie, who we know is Mind; both are singers/rappers, their routes involve dubiously ethical activities from other parties (Chixie's set gets stolen, Zebruh plots to trick Marvus), Zebruh butts his way into both and is romantically interested in them, Marvus is hiding something and Chixie literally hides her face to succeed. If not that, then he's probably Light, the aspect of attention and relevance. I could see either Prospit or Derse.
Also, he's certainly affecting Zebruh somehow. Anyone else notice how weird it is for Zebruh to not only show any interest in a higher-blooded troll but to state it openly?
Additional possible datapoint for my "Alternia is intentionally trying to be awful" theory, from Tirona's route, as pointed out by TVTropes' Nightmare Fuel page: Ceruleans can read minds, and can mind-control people to force them to tell the truth. They don't need to torture anyone. Considering the PC is a pretty nervous type, they may just be overreacting to normal sounds, but the possibility is worrying.
Anyone else mildly disappointed Daraya's quirk turned out not to be speaking like Ebony Dark'ness Dementia Raven Way?