Had never heard of a delver before........what a grand yet unassuming hero will be found in the personage of Ryson Acumen, the Delver.  He is surrounded by a cast of defining characters that, together, destroy Ingar's sphere which is entombed in Sanctum's mountain.  Since this is just Book 1, you will be happy to know that adventures continue through Book 8.  Join me in exploring the rest of the stories as I'm sure you'll enjoy them with me.