The Nightsiders series does not have a new book coming out soon. The latest book, Vault of Shadows (Book 2), was published in September 2016.
The first book in the Nightsiders series, The Orphan Army, was published in May 2015.
The Nightsiders series primarily falls into the Action Adventure genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.