Given how they look they're probably not identical but fraternal twin girls. But anyway, this seems like the standard protagonist abandonment setup, but the reasons for abandoning her are pretty thin right now. I hope the reasoning for these villains get fleshed out a little because they're looking a little too flimsy and one-dimensional for now.
I don't know if she'll actually seek revenge but we already know from the title that she'll be the one with true powers, so a schadenfreude/comeuppance chapter for her "family" is going to be a given and I'll be expecting that.