She's definitely a candidate. She's been in the company since day 1, siccing Selen on Petra while she stays silent and shadowy behind the scenes. When she gave the order, Petra was forced to join Lazulight.
Enna and Reimu are her simps. When Nina debuted, Rosemi knew her total control over the organizatiom would be threatened, so she preemptively isolated Nina, while also giving herself bigger tits in her second model to compete.
It took a long while to get her biggest competition, Selen and Pomu out of the scenes. They left because of management conflict, but that's the dirty little secret. Rosemi is actually a manager. She was promoted when Tazumi discovered that she was Chinese, and has been subtly influencing the managers to undermine their lead talents at every turn.
Rosemi describes herself as satan, but that's not just a cute joke. It's what everyone calls her behind the scenes, as he wrath is enough to get any a two week suspension.
I kmow somebody in NijiEN management, and apparently she got the entire AR concert live cancelled because "her outfit wasn't pink enough".
Now her only competition left is Elira, whose a challenging rival dut to the fact that she has the biggest breasts in the company. But she has plans for Elira...