Erend and Billy looked up. They saw a black creature flying around the tower. A moment later the creature' rider launched a red lightning bolt that shot towards the tower where the archer Elves were.
The Lightning strike was enormous and created a deafening sound. But unfortunately, the lightning strike hit something invisible and couldn't penetrate it.
There was some kind of magic shield that protected the main tower and the archer tower.
The black creature spun again swiftly towards another tower. They could dodge hundreds of arrows that came at them.
After that, the rider on the creature's back launched another lightning strike.
He keeps doing that. Spinning, dodging arrows, then launching a lightning strike which was again bounced off by the Magic shields of the Elves.
But he didn't give up. Instead, the numbers are growing. Suddenly two other flying creatures joined him.