User blog comment:Phantomlink959/V3C4 preview/@comment-26809978-20151126195200

I'm just gonna call this now.

Cinder will use her virus to infect the Atlasian Knight-200s to take over Vale. After that, she'll use the Knights to destroy the barriers protecting the kingdom from Grimm, probably by using all of the Atlas fleet. Once that happens, the Grimm will destroy the kingdom.

This is just speculation, but I seriously think this is what her plan is.