It's partially true.
I actually think of it more like the Puritans and england and shit. Tonberries used to be basically lizard-person sheperds. They used the lamp to keep the flock together. Since a lot of humans were xenophobic assholes, they would raid or kill the tonberry's herds. Tonberries were forced to the fringes of society and grew resentful, and because magical evolution is the shit, developed supremely good skills with knives, the same tools they used to prepare their food when they had to kill a member of the herd for a meal. Using their innate magic that they'd used to kill their beasts more mercifully, they turned it into a darker purpose. They never really set out on a crusade to destroy humans, but they sure as hell killed humans they found on their 'property', and since they felt a comradery with other monsters(even though a lot of monsters don't and didn't know what the fuck a tonberry even is), they would attack monster-hunting groups in counter-crusades. However, since this wasn't always successful, and would get a lot of them killed, they retreated further and further from the forefront of the world, growing more resentful, turning their hate into a sort-of religion. They shun most other monsters that appreciate humans in almost any way now, seeing them as traitors. This disassociation with humans did have one good effect; the number of males born increased. Not much, but from somewhere around 10% like most monster species to maybe 30% or so. Female tonberries tend to be faster, and male tonberries have more control of their voodoo-esque magic(yes, that includes the dolls and shit; Ton hadn't gotten to that part of her education yet), so which one is more dangerous is dependent on the victim.
But yeah, basically they're monster Puritans. Nobody really likes them, they don't really like anybody else, and they continue to herd cockatrices, basilisks, drakes, demonic spiders, etc.
One of the few monster species still on good terms with them, yet also infatuated with humanity, is malboros. And that's mostly because malboros are fucking fantastic farmers, which gives the tonberries plenty of vegetables and fruits, while the tonberries give them meat and such. They serve as basically the only anchor to the outside world that tonberries have outside their rural communities(again, typically in swamps, marshes, and ancient forests, as this is where their herds live best). These look somewhat like the Shire, by the way.
As for why Ton is around, well...the short story(that you would never find out in game because she doesn't fucking know) is that her parents were Tonberry merchants. One of the few to travel, and actually less racist and backwards than most tonberries(this should say something about most tonberries). They got killed by a religious monster-hunting order, and hid Ton first. When Ton was found by some monsters, they helped get her to Madness City, in sort of a dick way of saying 'she's your problem now'.
Oh, and also my new plot revolves around a splinter faction of tonberries thinking humans are starting to kidnap tonberries and so decide to go on a crusade against Madness City. They'll probably try to 'rescue' Ton, realize she's been 'brainwashed' and try to kill her as an abomination Have fun with 150+ Strength enemies! (If they can't auto-crit, they need bullshittingly high amounts of strength to give you the proper idea about how fucking scary tonberries are. Don't worry; there's only a few hundred
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