Didn’t know you were a warhammer fan, blood ravens really suit your personality. Could you assign each of the main rwby cast to a primarus space marine chapter (pre heresy) and see how the characters would interact with that knowledge?
If you weren't Anon I'd ask you what you mean by that.
Probably something about me 'stealing' art for stories.
But, I used to paint Crimson Fists, mostly because I got the Chapter Master of the Crimson Fists, Pedro Kantor so I made the rest of my army match them.
But, I eventually got some Primarus Marines, and couldn't think of an army to paint them, so I chose Blood Ravens. Although I have the colour wrong, it's meant to be a darker, more of dried blood red. My Blood Ravens red is more... freshly spilt blood red.
Now on to your ask: What chapter would best fit which RWBY character...
Okay, we're going on personality, and weapons, not their colour schemes.
Jaune would be... I would say an Ultramarine. He seems to fit the jack of all trades role they have. I'd say Rusted Knight Jaune fits a Custodian. Or, a Dreadnaught...
Nora is a Space Wolf. Her personality best fits a raging, drunk Space Wolf. Defiantly wields a power hammer. The big one at that!
Ren... Ren being a ninja, and all fits the Raven Guard. Quick, silent, and precise.
Pyrrha would fit the Blood Angels, more so for the beauty they embody, not the bloody rage aspects.
Speaking of a bloody rage...
Yang would fit the Blood Angels for her rage, and the Red Thrust...
Blake would also fit the Raven Guard for the same reasons I mentioned for Ren.
Ruby would probably fir the White Scars considering their fighting styles is based around speed. And, a I could see one of them using a scythe like weapon.
Weiss... I was having a hard job pinning her down, she'd defiantly be a Librarian. being a smarty pants, and her semblance. So... I went with the Chapter most known for being smart, and having an abundance of Librarians...
These are just my thoughts, if you've got better ones, then his me with your best shot.