Actually, flying creatures are rare in this world compared to land creatures. But flying creatures had the advantage in traveling, so more flying creatures could reach the green star earlier compared to the animals that needed to walk.
The defenders of the world waited day and night for the enemy. They couldn't do anything yet because the green star was intangible. It was as if it was in another space beyond them.
The only change to it was that it got bigger and brighter each day. Then one day, the green star solidified and then popped in a great flash of light.
This was during the day, yet the brightness made many creatures look away. For those who didn't look away, they saw that the spherical green star became a bright white star.
Then the white star disappeared, leaving behind a great metal stone in its position. The defenders of the world felt both relief and fear that the enemy had finally showed itself.
