You might think a dragon is an imaginary creature and it is not actually existent. Certainly, they have never be born in this civilization. But, in the past civilizations, there had been eras when they were living on the ground. You might not believe, but there is a place where dragons are reigning over a planet. That means the spirits like you are born to figures of dragon.
In the spiritual regions of the earth, they are only the existence who can move through the wall between dimensions. Your human spirits cannot move from the lower dimension to the higher dimension freely. However, dragon gods can go through the wall. There is a word 'Mitama-Okuri' or carrying-a-spirit, which means that a dragon god carries the human spirit on its body beyond the dimensional walls when he or she finishes the life of this world and gets back to the original spiritual region.
It is the role of a dragon god to make a spiritual barrier. There happens to make enormous hindrance by the beings of the demonic world when an important situation faced like in the current civilization. In such occasions, dragon gods protect the angels of light on the ground by making a spiritual barrier or shield, called 'Kekkai'. It is a dragon god who has been taking a very important role, where you are not aware of.