There are 3 books in the Diary of a Powerful Wither series.
The Diary of a Powerful Wither series does not have a new book coming out soon. The latest book, Secrets Revealed (Book 3), was published in January 2016.
The first book in the Diary of a Powerful Wither series, A Lost Past, was published in January 2016.
The Diary of a Powerful Wither series primarily falls into the Heroic Fantasy / Sword & Sorcery genre. This middle grade series was written for ages 8-12, but can be enjoyed by older readers as well.