All of Darren's early books were oriented to adults. He thought writing children's books would be a nice idea for the future but adult books were his main focus. His breakthrough came with Ayuamarca, written under his full name instead of a pen name. It was published in February 1999 by Orion Publishing Group, and did not sell very well. The sequel, Hell's Horizon, published in February 2000, was thought by some to be a better book, but sold fewer copies than the first. Ayuamarca was re-released in March 2008 under the title of Procession of the Dead and under the pen-name D.B Shan.Hell's Horizon followed in March 2009, and the third in the trilogy, City of the Snakes is set to be released in the UK in March 2010.