@Nightsky
I'm afraid that, if you're looking for a bully, Nadia would be the wrong demon for the job. Nadia's mean, make no mistake, but she
hates bullying. It's one of few lines she thinks is important not to cross. Nadia wouldn't have been present for Rain's early years, either, since she was actually raised on Earth by her human mother (she's
technically a hybrid, with some of the insecurity you'd expect from that) until her demon powers manifested and she briefly moved to Hell before being kicked out herself.
But if you're interested in Rain meeting an older half-sister she didn't know she had and has the potential for a positive relationship with, instead, I'd be happy to oblige. Nadia's not a good person and doesn't pretend to be...but she
can care, even if she has trouble expressing it properly.