The Green Man's War — Juliet E. McKenna

For a few years now, the Green Man has sent Daniel Mackmain to resolve clashes between ordinary people and the supernatural world. Dan has found allies among folk from myth and met other humans who can see the uncanny.He has also made dangerous enemies. Someone has decided to put a stop to this interference once and for all. Dan and his friends are about to find themselves in the firing line.A modern fantasy rooted in the ancient myths and folklore of the British Isles.