Curate, connect, and discover
I half want it to go like:
JNR Runs into Cinder again while Atlas is going to hell.
Jaune and Cinder end up tug-o-warring the lamp.
Jaune: Seriously! Why are you like this!?
Jinn: Well since you want to know...
And Jaune (and Nora & Ren (and Neo?)) get Tragic Backstory poured into their ears.
Could even play the long game with it, have it shown that they get told about it in the middle of action, but save anything but reactions and hints to the audience until things calm down again. Heck, you can have Team JNR narrate Cinder’s backstory to Team RWBY (and the audience), even have them still keeping some things hidden.
Jaune: And then, Salem found her...
Nora: Well, before that there was-
Jaune: Salem found her, Nora!
I remember hearing once that Cinder isn’t Ruby’s villain, she’s Jaune’s (and JNPRs as a whole), and I’ve only believed it more since. And having JNR seeing Cinder’s past like RWBY saw Salem’s would pretty much prove it permanently for me.
Sudden thought, think we'll learn Cinder's past in flashbacks like Ren and Nora's? Or that the heroes or one or two heroes will actually be told it or learn of it?
Nora : In my defense, I was left unsupervised.
Ren : Wasn't Jaune with you ?
Jaune : In my defense, I was also left unsupervised