The Underworlds series does not have a new book coming out soon. The latest book, The Ice Dragon (Book 4), was published in December 2012.
The first book in the Underworlds series, The Battle Begins, was published in April 2012.
The Underworlds series primarily falls into the Action Adventure genre. This chapter book series was written for ages 7-10, but some older readers may still like to read these books.