From publisher blurb:
Welcome to Engines of Destruction, the third in our line of Monster Menagerie monster books. Each volume in this line presents a small set of monsters tied to a single theme, but spread over a range of CRs. For Engines of Destruction, that theme is unusual constructs. Rather than presenting a gaggle of yet more golems made out of stone or metal materials, author Sam Hing has put together an awesome set of unthinking enemies that go beyond just walking statues. We have desert destroyers, simple constructs for beginning artificers, an animate slice of the void, and even self-motivated brewing equipment.
This collection can be helpful to GMs in many different ways. Since the foes within this book range from CR 1 to CR 18, they can augment the ranks of any squad of dungeon guards, wizard-lead armies, or mad alchemist's lab with something the players (and their characters) haven't seen before. However, they can also form the frame for a whole new threat if the GM decides to base an adventure around engines of destruction. Whether you introduce the characters to a small country ruled by a tyrant that maintains order with the literally iron grip of golem enforcers, or start a campaign where magic storms can create random constructs with bolts of arcane lightning, the engines of destruction can provide an ongoing problem for a group of player characters. Augmented with golems of wood, ice, and iron, the monsters provided here can form the backbone of an entire campaign arc-if a GM chooses to employ them in such a manner.
However you choose to terrorize your players, we're hopeful you'll find something useful in our third Monster Menagerie. Now, ready yourself for the first course of the animate army; the stomping, clanking, and grinding is a sign that the construct killers are approaching.
Remember some monsters aren't born. They're made.