Thunderbone: The X-Zone

When Lydia Rayn escapes an attack on her town, she runs into the woods and meets a boy who tells her than she is not who she thinks she is. There is another world living right next to her human world without her knowledge. He also mentions that in this world, the goblin world, she is one of the most feared and respected kind, and that the X-Zone has been trying to collect her for a while. She enters this world that she knows nothing about, and immediately the existence of the world rests on her shoulders. She is the one who has to fight for them because of her identity: she is a Thunderbone.