Yuki Yuna is a Hero:Churutto!

Year 300, Era of the Gods.
With the holy tree Shinju in danger, Heroes and Priestesses from across history were summoned to the world inside the tree.
Gathering together in the Sanshu Middle School Brave Hero Club’s club room, the army of 27 girls eventually came to be more like a big family.
With their powers combined, club president Fu Inubozaki hopes to create the legendary Brave Hero Club Udon!