Wrath of the Bloodeye

This book is called Wrath of the Bloodeye by Joseph Delany.
Tom Ward, the 7th son of the 7th son has being the spooks apprentice for almost 2 years. The Devil himself and his minions are after him. But for his spook trianing he must spend 6 months with Bill Arkwright, a fellow spook. He must leave his friend Alice behind and spend a long 6 months in a boggy swamp to learn about water witches. His training with Arkwright is brutal and intence. They fight eachother with sticks and play hide and seek with 2 wolfhounds. But as the story progresses he meets Bloodeye, the Devils daughter and a water witch. He learns that if the Devil's children kill him, he will rule forever. But if he kills Tom himself, he will rule a short 100 years. As the Devil freezes time itself and makes Tom battle a dozen water witches and Bloodeye in the damn marsh. As all seems lost he finds that he's not alone.