Again, he considered the distance between Earth and the front line.

There had to have been social contact between Earth and these other worlds before.

A major difference between the setting and Earth is the presence of magic.

Their power combined had created the link between wind and earth.

Believe me there is more between heaven and earth than we pretend to know.

Which is remarkable, considering the distance between Earth and this world.

In the meantime we are suspended between earth and sky.

For example, in a solar eclipse the moon gets between the sun and Earth.

We too have a role in the great war between Sky and Earth.

In the great war between Sky and Earth, we must play our part.