Goblin Slayer is aruably the hottest shonen title in Japan right now. The franchse started out as a light novel series in February 2016, written by Kumo Kagyu and illustrated by Noboru Kannatuki. Kōsuke Kurose illustrates a manga adaptation that started publishing in Monthly Big Gang manga magazine in May 2016. Many fans are patiently awaiting the news of an anime adaptation, however, there's just not enough manga chapters yet for such a project.
This is precisely why fans are excited that there's a prequel manga series from Kento Eida that's going to start publication on September 15 in Sheisha's Young Gangan magazine. Perhaps with this expansion of the source material, that coveted anime adaptation announcement will arrive all the quicker?
Yen Press currently releases the English-translated manga chapters, with the 15th chapter being released on August 25.