Yuuki Yuuna Is a Hero - Season 1 Episode 2 Noble Thoughts

With the Vertex able to regenerate its wounds, Fu has Yuna and Itsuki perform a sealing ritual in order to expose its core. Working together, Fu and Yuna manage to destroy the core, defeating the Vertex and returning everyone to the real world. The next day, Fu explains that she was tasked by her organisation, the Taisha, to grant hero candidates the power to fight against the twelve Vertex that threaten Shinju. Mimori, frustrated that she couldn't help everyone during the battle, directs her anger at Fu for keeping things a secret from everyone, but Yuna manages to cheer up a little. The girls are soon brought into another battle as three more Vertex emerge, using combined attacks to keep them from performing the sealing ritual. When the Vertex start attacking Yuna, Mimori becomes determined to protect her and awakens her hero form, using long range attacks to provide support, and together they manage to defeat all three Vertex.