Design Delve - Dealing with High AC in D&D 5e

In yesterday's post, I wrote about how GMs can lean into characters with high passive perception to enhance the gameplay experience for the whole table. Today, I'm going to explore the other side of that coin - dealing with characters that have high Armor Class (AC). 

Characters with high AC have more of an impact on combat than characters with high passive perception. As a result, I feel they're harder to deal with for new GMs. Learning how to run a character with high passive perception well doesn't require the same game design prowess as dealing with a character with high AC. My hope is that this post can provide you with some ways to handle high AC characters without making the game less fun for them or your other party members. 

Why Is High AC A Problem?

For some GMs, a high AC creates a fear that combat becomes trivialized for the high AC character - especially at lower levels where enemies may have less access to spells or other tactics that can endanger high-AC characters effectively. 

As a result, many GMs start balancing encounters to ensure that enemies can hit the high-AC party member at least semi-often. Of course, this inevitably leads to enemies hitting the rest of the party almost constantly, making combat feel punishing and unenjoyable. 

On the other end of the spectrum, GMs may not understand how to give high AC characters an enjoyably challenging experience in combat - you don’t want them to feel safe all the time - making the experience less fulfilling for said player. 

Neither outcome is good. To run a high AC character well, we first need to understand why players want high AC to begin with, and then utilize various methods to provide high AC characters with challenges that still honor their build choices and make the game fun for the rest of the table. 

Kim Junghun

Why Do Players Love High AC?

Players tend towards optimization because it gives them more control over the gameplay experience. It's the same reason you may want to grind out some great armor in a videogame, or solve optional puzzles to get a powerful weapon - you determine that expending extra resources will make the rest of the game more enjoyable for you. 

Players want high AC for the same reason. They want to feel unhittable. They want to reduce the chance of their character dying. They believe that a high AC will enable them to fulfill these desires and make the overall gameplay experience more enjoyable. 

If you have a character who's clearly building toward a high AC, it's important to understand exactly what their fantasy is. I find most players who tend toward high AC want to:

• Feel acrobatic and squirrely. This is often achieved by maxing out DEX, finding some studded leather, and attempting to play a dextrous combatant, such as a swashbuckler rogue, monk, or bladesinger wizard.

• Feel powerful and intimidating, able to take it as well as they can dish it. This is typically achieved by going for heavy armor and high STR, although barbarians may lean more into CON or DEX. Fighters, barbarians, and paladins are a favorite for this kind of playstyle.

• Protect their allies and draw attention. Heavy armor, a shield, and a focus on STR seem to be favorites among players with these goals, although light armor and high DEX can work just as well. I’ve seen plenty of barbarians, paladins, fighters, and artificers lean more towards pure tank.

With regards to the last point - it's worth noting that many players who go for a "tanky" build and attempt to optimize may also want to pick up Polearm Master and Sentinel, otherwise enemies can just run past them. If you're dealing with a new player who wants to "tank" for the party, consider pointing out feats such as Sentinel or spells such as Compelled Duel and Warding Bond to help them live out that fantasy. 

Ultimately, while players may tend toward high AC for different reasons, the fantasy at the root of all these builds is the same - the player wants to be hard to hit. So let them be hard to hit.

Players who go all out maximizing AC are also sacrificing other opportunities to be difficult to hit. By trying to ensure that enemies can consistently high a high-AC character, you're invalidating the investment they've made in their build.

Similarly, if you try and make a high-AC character hittable, you're going to end up murdering other characters with lower AC because you've skewed the average enemy hit chance too far toward the high-end. Allowing a high-AC character to be hard to hit is a win-win that makes the high-AC player feel rewarded without punishing the rest of the party.

Caio Monteiro

Challenging High AC Is About More Than Spell Saves

The default suggestion for new GMs dealing with a high-AC character is to simply target them with spells that require a save the character is weak at. 

While that's definitely an effective tool to have in your arsenal, I'd caution against using spells as your sole method of combating a high-AC character for a few reasons:

• Being incapacitated feels bad. Being slowed, stunned, or mind-controlled never feels good as a player, and if it happens often, it will get old and make the player feel unfairly targeted. Getting hit by a monster for 10 damage often feels much less punishing than being taken out of the action entirely, so handle with care when using spell saves to counter high AC.

• It can feel manufactured. If all you have as a counter to high AC is spell saves, expect a lot of “jokes” from your high-AC player about how they can't wait for every fight to include some spellcaster that can fuck them up.

• It harms the authenticity of the world. This point goes part in parcel with the above - incorporating spell casters or magical traps into every encounter eventually starts to break apart the coherency of the fiction in most games and settings.

To present your high-AC character and the party with challenges that don't take away from any player's fun, I suggest the following:

• Play enemies intelligently. Smart enemies will try and avoid the guy that can't be stabbed easily if they have a shot at the dude in cloth long-johns holding a book. Having an enemy or two attempt to lock down the high-AC character while the others focus on the squishier party members forces your party and high-AC character to think about their environments tactically and gives everyone decisions to make on a turn-by-turn basis. It may also inspire your high-AC character to lean into feats and spells that help them fill the tank role if they really want to… you know, tank.

• Utilize verticality in encounters and enemies with ranged attacks. Having arrows raining down toward the party past the frontline not only gives everyone an issue to solve, but can also make your high-AC player feel powerful as they advance through a hail of arrows (relatively) safely.

• Work high AC spotlights into the story and encounters. Throw in a chokepoint every once in a while that lets your AC tank hold off multiple enemies through sheer dexterity or quality of armor. Once they’re high enough level to have gained some recognition, have commoners recognize them as “the bulwark of Borovia” or some other similar fitting moniker. Have an infamous duelist seek them out and challenge them to see if “you’re really as hard to hit as everyone says.” This is the stuff that, at the end of the day, the player will remember as a highlight when all’s said and done.

Like a character with high passive perception, dealing with a character that has a high AC can be uniquely rewarding for GMs and players alike with a little time and effort. I had a lot of fun writing this little two-parter for my Design Delve series - hopefully, you had fun reading it! Stay tuned for more in the near future.