My-Otome - My-Otome Zwei (2006)

One year after the events of Mai-Otome, an asteroid on collision course with Windbloom kingdom is destroyed — barely — by an international task force of Meister Otome. Subsequently a new and more powerful kind of Slave appears, along with a sinister black-robed entity — or entities — able to easily overpower the most powerful of Meisters. Not only that, but Arika and Mashiro's troubled relationship is hindering the use of the Blue Sky Sapphire — possibly the only weapon powerful enough to defeat the new adversary.