For lurkers: This is a warning and a disclaimer. I'm not too anal about authorship over fan work, but if you are a RWBY fan of all people and you come across this thread on the internet and like this idea enough to want to steal this, I wouldn't think of doing it knowing you'll be taking it from what is essentially "the internet's underworld". Shit can be traced back. People will and can learn, and they will look at you funny. I weep no tears losing this idea, but my sense of decency warrants this. Unless you know what you're getting into, taking stuff directly from this place is like stealing from the mafia. Again, know what you're getting into.
The world of My RWBY Remake is now named Fable, not Remnant. Remnant sounds like it would be better for a world in an edgy, brooding Evanescence inspired world.
Fable is a world that is run on an energy known as Mythos. Mythos is created through the actions of people and phenomena of the world; it doesn't have to be full hands on athletics or being out there in the world, as long as that action is something done by one's own free will and volition, or is a force that runs the universe. Mythos has a complex system behind it, with varieties, attunements, interactions with human physiology, spiritual body metaphysics, etc, but at the same time, it can be summed up with the phrase "it just works".
The people of Fable have lived in a precarious existence against monsters known as the Grimm (really original I know). Grimm are lifeforms that have been considered to embody the negative side of all things, and though while an abomination of terror upon both nature and mankind, they are necessary for the environment. Grimm have long been studied but due to their uncanny ability to hunt and fight, progress has been extremely slow to advance in this field. Grimm tend to dwell in places that have been "grimmified"- essentially marked with their Mythos as their territory, and causes the location in question to become soaked in negative energy, causing the environment to aid them in someway. Unlike the retarded version in vanilla, they do not become attracted merely to negative emotions, instead they are more like predatory animals or careless creatures that think they own everything. There are also people who seek out the power of the Grimm as well.
Against the Grimm, the people of Fable have fought to protect their lands from being taken over and grimmified and from being preyed upon. Long throughout the ages, those with the power of Mythos were acknowledged as heroes and saviors of the people, or villains and scourges of the land. Overtime, as the secrets of Mythos were unraveled, and as civilization progressed, more people were able to realize their powers of Mythos, and were able to join the ranks of these people of prodigal attained transcendence. These people able to realize their Mythos are known as The Storied.
Into the present day, young people who aspire to become Storied join private schools known as Prime Studies. Prime Studies are not end all be all academies; they are where many Storied of many walks of life come to associate and share their knowledge and methods. This means there are "job classes" like in JRPGs to different professions and occupations that require study of Mythos.
Our story begins as Ruby comes home from normal people school, putting time into her workshop. She is putting the finishing touches on her signature Ruby Rose scythe rifle, and she completes it, and goes to test it out. As she is testing it out, a flood of Grimm rush over her neighborhood. She fights them and stuff, but because she is not experienced, she is nearly food until some Storied come to save her. After she gets out from the hospital, the heads and scouts of PS Emeraloz, the premier Prime Study of her area, take note of her ability and her weapon. They ask if she wants to join. Ruby says yes.
Now to Characters:
Ruby: Ruby is now a hardcore weapons and mechanics wrench wench geek who loves creating weapons as a craft, an art, and a way of life. While she helps to create and upgrade weapons, she likes to make her own trademark weapons themed after the moon, the night, and red roses. More than just her scythe rifle, she has many other weapons, like a saber gunblade, a double end rose motif maul tipped Mythos emananting staff, and other stuff.
Weiss: Weiss is an aspiring dancer who is trying to make it on her own away from her rich family. She is able to use summoning magic.
Yang: A problem child martial artist who gets into street brawls and has an on-off relationship with her dojo. She doesn't have those gay gun knuckles and she is able to use Mythos ki/chi style. She does eventually gain access to new Mythos storing weapons that Ruby has been working on, being sleek gauntlets and greaves like armor that allow her to harmonize and use outside Mythos.
Blake: She wields a katana. All I get from her is Hiei vibes, but I can also imagine her being the team's "black mage". I also am bringing back her Faunus racism arc and having her personality be more, actually affected by this. She initially hates the fact that she has to team up with her group in P.S. Emeraloz because they're humans, but hides this with some mask of smiles and passive aggression. This hampers their team dynamic and she is confronted over this, being demanded to shape up or she will be expelled. She has a lot of baggage but she eventually gets better. She still has some harsh sentiments against humans however, but not her friends or anyone generally decent.
I dunno if you want more let me know.