Cygnuses are unavailable.

That would be awesome and it's very likely that the Cygnus Knights revamp only happened now because there's more motivation to fight. In particular, this reminds me of that teaser with the more adult-looking Cygnus a while back that mentioned her saying that she has to use the power but that could be a reference only to reviving Shinsoo.

Still, given the circumstances I doubt that that's all. I would also like to see if the Cygnus Knights take a somewhat darker bend due to what Damien did to Shinsoo.

Yep, this one:


In the video it looks like she is quite literally gearing for war.
She's been overseeing the events of the alliance for a while now, and hasn't been THAT much use, outside of finding the World Tree or liberating Azwan.
Ereve has been attacked before, but her Knights have always managed to fend it off, and then comes someone who is too powerful for them to fight, who kills someone dear to her. It seems clear that her first thoughts would be "We need to get stronger, I need to get stronger"

And then she goes and makes a contract with Kyuubey and transforms all Magical Girl style. "your wish has surpassed entropy"