Please stop persecuting your students!

Saki: "This means I am the acting principal of Tenjin Elementary School."
Joan of Arc: "It is our duty to restore the glory of the heroes"
Yagami Taichi: "Tell me, I will protect everything in the Digital World"
Nia: "It will be a success if I don't lose the female lead position!"
Miyu: "It's a success if I can pick up Illya!"
Yagami Hikaru: "I've caught you...ah, it's okay"

Simply put, it is a story about a teacher who stepped forward to save a school on the verge of bankruptcy (not really), and led his increasingly unruly students to save the world (not really).
This book contains: XB2, XB3, Digital DA, Moyi, Gundam, Tatakai, SAO, No Job, Shugo Chara, Witch, Fader, Kaguya and many other elements, the composition is not complicated
This book is also known as: I like Nia and everyone, This acting principal has a problem with his brain, Welcome to Tianshen Elementary School, etc.
The only designated female lead: Nia Haiyudaga (tentative)