At last month’s Gen Con, we set loose a pack of new monsters on the Iron Kingdoms with the release of the Iron Kingdoms Full Metal Fantasy Monsternomicon.

Writing the Monsternomicon was, for me, a return to my roots. Some of my first work in the game industry was as a freelancer, writing about monsters for roleplaying games. I’ve never written about them in quite this way before, though. One of the core principles that drove development on the Monsternomicon was the idea that each monster should feel like a real creature.

This may seem strange when the creatures you’re talking about are soul-eating monsters or exploding rats, but it was fundamental to our work on the book. No matter what kind of creature we were writing about, we approached each with a naturalistic perspective, almost like we were writing a manual on the wildlife of western Immoren. Each creature needed to fit into the extensively developed world of the Iron Kingdoms. Rather than just worrying about how deadly it was and how much vitality it had, we started asking questions about where the creatures commonly live, what their behavior is like, and how they interact within their social groups and with other creatures that share their environment.

This all needed to make sense within the larger world. For example, the dracodile is a massive apex predator, which means it would control a huge swathe of wilderness. Most habitats can’t support more than a few dracodiles; there simply wouldn’t be enough fish, meat, or gobbers for them to eat. We took all of this into consideration when writing about the dracodile, and we incorporated its territoriality and protectiveness of its hunting ground into account. This kind of background material translates over to the rules.

Revising the older Iron Kingdoms creature entries presented whole other challenges. The previous iterations of many creatures, due to the system they were designed for, had various strange rules tacked on—for instance, Blighterghast was super good at oceanography.

While writing the rules for the new Monsternomicon, we looked at what the creatures were able to do in the past (trimming away any superfluous skills they might have picked up along the way) and combined this with our new understanding of them as realistic animals to distill rules that reflect their place in the Iron Kingdoms. Early on, we started adding Sneak and Detection to anything described as an ambush predator, while more aggressive and active hunters typically wound up with pretty decent Tracking skills. As we wrote the rules, we had to keep in mind the upcoming release of Iron Kingdoms Unleashed, and ensure each creature worked within the constraints of both Full Metal Fantasy and Unleashed.

So that’s a little insight into our approach for Monsternomicon. Monsternomicon will be in stores Wednesday! Visit your local game store to get your copy, and add some life–or undeath–to your Iron Kingdoms adventures!