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Rules Compendium
Ampersand Special: Essentials Previews
by Bill Slavicsek

Hi. This is another of our special free-to-all editions of my regular column. I’m talking about our Dungeons & Dragons Essentials products throughout this month and next. We just returned from the fun and excitement of Gen Con, and now it’s back to our normal routine.

For those of you who weren’t able to make it to the convention, check out our coverage of it. We’ve got pictures, seminar logs, and podcasts of many of the key Wizards events that took place over the course of the long weekend. We had a lot of fun talking to fans, playing games, and revealing secrets about upcoming products. Next up for us—PAX, here in Seattle in a few short weeks.

Now let’s get back to my continuing revelations about the new Essentials products. This week, I want to talk about the Rules Compendium. This digest-sized paperback provides 320 pages of game rules and debuts in September. The book not only explains the basics of the Dungeons & Dragons roleplaying game but also contains detailed rules and commentary for seasoned gamers. Other products might be designed specifically for either players or Dungeon Masters, but the Rules Compendium is for everyone at the game table.

The Core Rules All in One Place

The rules of the Dungeons & Dragons roleplaying game have traditionally been split into two categories—rules for players and rules for Dungeon Masters. Further, these rules have consequently been presented in two different books, the Player’s Handbook and the Dungeon Master’s Guide. Getting a complete picture of how the game works has required reading both books, as well as the smattering of rules in the Monster Manual. That division of information has been practical, given the large scope of the game, and it is an arrangement that many of us are used to—particularly those of us who have been playing the game from its earliest versions. The downside of this division is that readers sometimes need to flip through two or three books to find a particular rule and sometimes can’t find the rule at all.

The Rules Compendium puts all of the rules of the game in one place. This is the rulebook for the core game, whether you’re playing Gareth the cleric or DMing an epic campaign. This is the go-to book for how to make a character, decipher a monster stat block, play through a skill challenge, launch into a battle, and engage in any of the other fundamental activities of the game.

The new Rules Compendium is a comprehensive game reference, but it goes a step further; it tells you how to play the game. If you have the Rules Compendium, you have the information you need to use things like the powers in your player book and the monsters in your DM book. You still need to go to those other books for particular game elements, such as powers, monsters, and magic items, but you need only this book to understand how those elements fit into the game as a whole.

Because of the book’s focus on the game’s core, some rules didn’t make the cut. Rules for artifacts, for instance, aren’t included. In contrast, every power keyword that has appeared in our books is defined. The book also includes things that aren’t rules but provide context for understanding the game, which is a combination of game play and storytelling. For example, alignments are defined, since alignment is a core story conceit of the Dungeons & Dragons world.

Rules Updated and Clarified

One of our goals for the Rules Compendium was to make its rules as up-to-date and clear as possible. To achieve that goal, we have incorporated every update to the core rules that has occurred since the current edition of the game was released. “The book includes updates like the revised Stealth rules, the changes to how weapons and implements work, and new DCs for various tasks,” explains Jeremy Crawford, senior developer and lead on this project. “The revisions that we introduced in Player’s Handbook 2, Player’s Handbook 3, Dungeon Master’s Guide 2, Monster Manual 2, and Monster Manual 3 are all included. When the book is released, it will contain the most current version of the game’s rules.”

We have also clarified many parts of the game, especially those parts that have provoked the most questions. You will find many new examples as well as commentary. Take conditions: their section of the book not only includes the nuts and bolts of how conditions work but also addresses some of the questions that come up in play. For example, players sometimes wonder, “Can an ooze or a snake be knocked prone?” The Rules Compendium says yes and suggests what’s going on in the game world when that amorphous or limbless creature falls prone.

As we worked to clear up as many rules as possible, we also came across portions of the game that needed more than a new example or a fresh turn of phrase. Some pieces begged for revision, particularly subsystems that were overcomplicated or simply no fun to play. For example, we have tightened up the rules for flight, and those rules now appear with the other movement rules, not in a DM-only section. Similarly, we have tweaked how mounted combat works so that it is easier and more fun to include in an encounter.

Every revision we made is meant to work with the material already in print. You will be able to take a flying monster from the Monster Manual, for instance, and use it with the slimmed-down rules for flight without needing to change anything in the monster’s stat block.

Looking Forward and Backward

The Rules Compendium represents the current state of the game, reorganized and fully indexed. The book lays the foundation for products to come, and it is rooted in the material that came before it. This collection of rules, examples, and explanations is a resource both for people coming to the game for the first time and for gamers who know the system inside and out. Our hope is that when you’re at the game table and wondering about something like, “What happens when my wizard tries to teleport the ogre straight into the air?” you will know where to go for guidance—the Rules Compendium.

Rules Compendium Preview

Here’s a chunk from the upcoming Rules Compendium that covers the resistances, vulnerability, and immunity rules. These rules are cleaned up and much easier to reference now, showing how the Rules Compendium immediately improves play at your table.


Resistance means a creature takes less damage from a specific damage type. Resistance appears in a stat block or power as “Resist x,” where x is the amount that the damage is reduced, followed by the type of damage that is being resisted. Damage cannot be reduced below 0. For example, a creature that has resist 5 fire takes 5 less fire damage whenever it takes that type of damage.

Some creatures are inherently resistant to certain damage types, as noted in their stat blocks, and some powers and other effects grant temporary resistance.

Against Combined Damage Types
A creature’s resistance is ineffective against combined damage types unless the creature has resistance to each of the damage types, and then only the weakest of the resistances applies.
Example: A creature has resist 10 lightning and resist 5 thunder, and an attack deals 15 lightning and thunder damage to it. The creature takes 10 lightning and thunder damage, because the resistance to the combined damage types is limited to the lesser of the two (in this case, 5 thunder). If the creature had only resist 10 lightning, it would take all 15 damage from the attack.

Not Cumulative
Resistances against the same damage type are not cumulative. Only the highest resistance applies.
Example: If a creature has resist 5 cold and then gains resist 10 cold, it now has resist 10 cold, not resist 15 cold. Similarly, if a creature has resist 5 cold and then gains resist 2 to all damage, the creature still has resist 5 cold, not resist 7 cold.

Combined with Vulnerability
If a creature has resistance and vulnerability to the same type of damage, they both apply. Subtract the smaller value from the larger one and apply the result. For instance, a creature that has resist 5 fire and vulnerable 10 fire is treated as if it has vulnerable 5 fire.


Some creatures are immune to certain effects. If a creature is immune to a damage type (such as cold or fire), it doesn’t take that type of damage. If a creature is immune to charm, fear, illusion, or poison, it is unaffected by the nondamaging effects of a power that has that keyword. A creature that is immune to a condition or another effect (such as the dazed condition or forced movement) is unaffected by the stated effect.

Immunity to one part of a power does not make a creature immune to other parts of the power. For example, when a creature that is immune to thunder is hit by a power that both deals thunder damage and pushes the target, the creature takes no damage, but the power can still push it.


Being vulnerable to a damage type means a creature takes extra damage from that damage type. Vulnerability appears in a stat block or power as “Vulnerable x,” where x is the amount of the extra damage. For instance, if a creature has vulnerable 5 fire, it takes 5 extra fire damage whenever it takes that type of damage.

Against Combined Damage Types
Vulnerability to a specific damage type applies even when that damage type is combined with another. For instance, if a creature has vulnerable 5 fire, the creature takes 5 extra fire damage when it takes ongoing fire and radiant damage.

Not Cumulative
Vulnerabilities to the same damage type are not cumulative. Only the highest vulnerability applies.
Example: If a creature has vulnerable 5 psychic and then gains vulnerable 10 psychic, it has vulnerable 10 psychic, not vulnerable 15 psychic. Similarly, if a creature has vulnerable 5 psychic and then gains vulnerable 2 to all damage, the creature still has vulnerable 5 psychic, not vulnerable 7 psychic.

Combined with Resistance
If a creature has vulnerability and resistance to the same type of damage, they both apply. Subtract the smaller value from the larger one and apply the result. For instance, a creature that has vulnerable 5 fire and resist 10 fire is treated as if it has resist 5 fire.

Next Week

Next week, we’ll dive into the Dungeon Master’s Kit to see what’s in that box full of DMing goodness. Until then …

Keep playing!

In Case You Don't Know Him

Bill Slavicsek's gaming life was forever changed when he discovered Dungeons & Dragons in 1976. He became a gaming professional in 1986 when he was hired by West End Games as an editor. He quickly added developer, designer, and creative manager to his resume, and his work helped shape the Paranoia, Ghostbusters, Star Wars, and Torg roleplaying games. He even found some time during that period to do freelance work for D&D 1st Edition. In 1993, Bill joined the staff of TSR, Inc. as a designer/editor. He worked on a bunch of 2nd Edition material, including products for Core D&D, Dark Sun, Ravenloft, and Planescape. In 1997, he was part of the TSR crowd that moved to Seattle to join Wizards of the Coast, and in that year he was promoted to R&D Director for D&D. In that position, Bill oversaw the creation of both the 3rd Edition and 4th Edition of the D&D Roleplaying Game. He was one of the driving forces behind the D&D Insider project, and he continues to oversee and lead the creative strategy and effort for Dungeons & Dragons.

Bill's enormous list of credits includes Alternity, d20 Star Wars, The Mark of Nerath Dungeons & Dragon novel, Eberron Campaign Setting, the D&D For Dummies books, and his monthly Ampersand (&) column for Dragon Magazine.

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