Mark Gibbon, using the pen name O'Neill, published the second book in the Cloch Mór Lore series. The title is Cloch Mór Lore II Dark Matters. It follows the first book, Cloch Mór Lore Kilbroney.

Gibbon declined a publishing offer for the initial volume to issue it independently. The series centers on an overarching narrative about a figure called Demon Brony. Stories incorporate elements of local history and folklore in a folk-horror style.

This volume divides content into sections on Rostrevor and Warrenpoint. Gibbon incorporated accounts shared by local residents. Future books include planned third and fourth installments.

Tales reference sites such as Cloch Mór Stone above Carlingford Lough, Kilbroney Park, Ballynagelty, Crotlieve Mountain, and Narrow Water Keep. One account involves a souterrain discovered during construction at Lassara Heights and Rath Cuain in Warrenpoint.

The book is sold at ELK Books in Warrenpoint and The Bookshelf in Newry. Copies are also available on Amazon in print, ebook, and audiobook formats.