Checkmate

//This is the story of a comic I'm drawing. I'm writing it so it helps me for the comic. Also, please tell me if you find any error! It'll be appreciated!\\

A legend says that a war was dividing the world in two. The first half was the magical creatures, and the second half, the non-magical. The two halfs were destroying each others when, one day, a girl came from the sky and told them to stop. The two parties, angered by the girl, tried to kill her, without success. The girl told them to stop, once again, but they would continue to battle. She lit the forest on fire and said, clear and loud "If anyone dares to attack someone else, I will light their army on fire". Afraid of what she said, they made peace.

Centuries after, peace is still there. Everyone is happy, and everyone helps each others.
But...
Now, a new ennemy is rising.
The enemy is strong.

So, what is gonna happend next?