What is Arbiter of Worlds?

My book, Arbiter of Worlds, is the definitive guide to building and running fantasy role-playing game campaigns. It’s a primer that will teach you how to build living, breathing worlds for your players to explore; how to host game and manage game sessions; and how to create powerful experiences of adventure that your players will talk about for years to come.

This blog is the companion to the book, dedicated to the art and craft of gamemastering, game design, and worldbuilding. It will also cover topics of related interest, including design updates on my own work, product reviews, and various musings and missives.

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This is a free Substack blog. By subscribing you’ll get the articles and essays delivered to your inbox. If you’d like to sign up for my premium content, I have a Patreon for each of my two role-playing games.

Buy the Book

Arbiter of Worlds is available exclusively on Amazon. Click here to get your copy now.

“Every Macris campaign starts with a rich, open world; the edge of a massive map; and the ability to find adventure in any direction. After playing in a dozen of his campaigns, I can assure you that Macris is the best prepared, most thorough GM on the prime material plane. He balances “deadly adversary” and “the party’s greatest supporter” perfectly. I’ve been lucky to contribute to some renowned video game worlds, and to discus world design with some of the most accomplished writers alive. And I’m honestly not sure there’s been someone more thorough at and passionate for world building than Macris since ... maybe Tolkien? (Okay, maybe G.R.R. Martin, but he’s not as organized or efficient.) It takes organization, creativity, and careful technique to build a massive world efficiently and deliver it effectively, and Macris can show you how he does it.” - Dr. Michael Capps, award-winning videogame executive, writer, designer (*Gears of War*, *Fortnite*, *Unreal Tournament, Unreal Championship*)

“Armed with decades of experience as both a player and a designer, Macris cuts to the marrow with razor sharp insights in an unapologetic and often painfully insightful analysis of every imaginable facet of being a Game Master. From implication of play inherent in a game’s design, to world building, to the often delicate nature of unspoken social contracts inherent in the hobby, the guidance found in Arbiter of Worlds is a much-needed breath of fresh air to veterans of the hobby and a forged-in-the-fire bootcamp for those taking their first steps behind the screen.” - James M. Spahn, Ennie and Origins Award Winning RPG designer

“A superb read. He makes his points the way you would expect a Harvard-trained lawyer to do. If you read this book, you are going to come out knowing real things you did not know before that will help you run games at the table…” - Courtney Campbell, Hack & Slash

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Designing games, running RPGs, and building worlds


I am the writer of Arbiter of Worlds and Star-Spangled Squadron; designer of Adventurer Conqueror King System, Ascendant, Domains at War, and Modern Spearhead; and founder of The Escapist.