I am now firmly on the camp that Ronova is the youngest among the shades because of how her bet with Xblanque went. She agreed to help with the only caveat being that if she got found out, she'd tell Phanes that Xblanque stole her power as if that'd solve everything, she's so naive
She probably saw the other Shades doing their own thing without getting find out, decided to try doing the same, and then got found out and punished. Can you imagine how that exchange went??
>Phanes: Why did you give a portion of your power to a mortal?
>Ronova: It wasn't me, that dastardly Xblanque stole my power~
>Phanes: And how did a human manage to stole your power? Did you go down to Natlan, told him how to do it, then fell asleep so he could put it to practice? Do you take me for a fool? Were you really this foolish? Why can't you be like your older sisters?
I can just imagine Ronova looking down, clasping her hands together just like when she's talking about Asmoday in the trailer, while Phanes gave her a verbal smackdown that emotionally traumatized her enough to become the most obedient Shade who's obsessed with following the rules. And that's like the best case scenario, for all we know the punishment is worse than just a verbal lashout...