From publisher blurb:
Each release for Crawthorne's Catalog of Creatures for the Pathfinder RPG presents a single, new creature for your Pathfinder RPG game, as presented by the famous and retired monster hunter and adventurer, Lord Crawthorne. Each release presents game stats for the new creature, as well as three adventure ideas to help insert them into your game.
As part of their variation on fey religion, the Treeshadow believe they have been charged with protecting their kin from outsiders, whether they like it or not. These dark fey do so with violent and intent and means, making best use of their ability to merge with trees to enhance their strength and hide from unwary intruders until the time is right to spring their ambush.