Spectred Isle

This is an interesting use of English folklore and includes all my favourite bits - ghosts, real history, magic, and archeology.
In this book, the Green Man is more than just lore, and whose power is the crux of a spell that holds paranormal denizens from hell at bay. Randolph, a kind of mage with a long family history, and his fellow Green Men, which include a ghost hunter and two Government-created mutants, are tasked at protecting England from what most of its citizens don't even know exist. The Government looks to use them to their own ends but the Green Men only work for King and Country and the new establishment doesn't jive well with that. Saul Lazenby, an archeologist that made some bad decisions in the War that got him dishonorably discharged, jailed, and ultimately disowned by his family, finally finds work with an eccentric Lord with a taste for the occult that leads to him crossing paths (and more) with Randolph.

More great characters from K.J. Charles and a completely unique story makes this a really fun and interesting recommend.