I didn't played that much of RA yet to have a chance to find her (at least is what I think), but based on my experience with the mode and a quick read of her mechanic, she probably would be my deadend (or no, who knows)

She is a boss from the "main story" of the mode. Having to block her with a damage dealer, and constantly CC her so she doesn't one-shot them is annoying, also you have to deal with the mob waves PLUS her all in two acts, because everyone respawns the following day.