I Made a Contract with a Dragon Princess at the Beginning. Princess, Please Forgive Me.

(Also known as: I contracted with the dragon princess at the beginning, I am invincible) Five hundred years ago, in order to resist the attack of the demon. Humanity launched a resistance and awakened a magical power in an accident. This magical power allows humans to make a contract with a kind of holy spirit called a holy beast. Human beings have used the power of the Holy Spirit to fight against demons for hundreds of years, and finally fought against demons. A college of the Holy Spirit was opened, and in this college. Humanity will learn how to use its own aura to fight with the Holy Spirit