Books with author Leo Forerunner

This story is about a boy who after running into a mysterious girl at a mall ends up with an old, large brown leather book, that hold secrets millennia ahead of anything on this earth. When the boy named Leo opens the book and sees the secrets in the book, he will find out that he has become a part of a war that will challenge not only his physical and mental abilities but his spiritual abilities as well. During this war he will become a great leader but will question everything about himself.