Torching (acidifying, electrifying, poisoning, freezing) the whole party with a dragon’s breath weapon is hands-down one of the most fun moments as a Dungeon Master. In 5th Edition D&D, the DM rolls a ton of dice and players save for half damage. The breath weapon recharges at the beginning of the dragon’s turn if it rolls a 5 or a 6. For easy mode, roll at the end of the dragon’s turn so the players have metagame knowledge of whether the breath weapon is in play.
This mechanic is good, but I’m a tinkerer.
Points of Improvement
I hesitate to call these “issues” because I don’t think there’s anything broken about the breath weapon. They run great. There’s give-and-take with any design mechanic. So, consider these areas of opportunity.
Whether you’ve played with or against a dragon, you know the breath weapon is brutal. As well it should be. You want the dragon to be fearsome (beyond the frightful presence). Still, it’s a little too punchy. I have seldom rolled out a dragon that doesn’t drop at least one party member with the breath weapon on turn 1.
Check out this comparison of red dragon breath weapon damage vs. player character HP:
The blue bars represent player HP at each level, with darker being bigger hit dice. You can see the assumptions made for Constitution along the x-axis. The red boxes cover the range of damage, with the red dots representing average damage. You might also note that the levels for the breath weapons don’t line up with the CRs of the dragons. That’s because the chart is based on the guidelines in the Dungeon Master’s Guide for a single creature against a party of four adventurers, which you can find handily summarized in the Encounter Building Unearthed Arcana. After all, dragons aren’t too good at keeping company.
While not a huge deal, randomness can cause narrative dissonance. It feels weird when the breath weapon doesn’t proc for a few rounds and then goes off twice. I want the recharge to have a more natural progression, as the dragon builds back up the power.
This is a worthy sacrifice to get away from the accounting of how long it’s been since the breath weapon last went off. Nothing breaks immersion like quizzing the party on the last rounds of combat.
I know what you’re thinking: here comes a crazy mechanic that you’re going to need an entire splatbook to understand. That’s not how we do things around here. The best solution is an elegant little tweak so you don’t throw off the balance elsewhere.
The breath weapon’s damage dice become the breath weapon damage dice pool. You can spend any number of damage dice when making a breath weapon attack. You recharge a number of dice every turn equal to 1/3 of the total dice pool.
Here’s a handy chart for rounding the 1/3 recharge damage:
Your Adult Red Dragon has a breath weapon that does 18d6 fire damage. On turn 1, you make a breath weapon attack to show the party you mean business. You spend 12 of the 18 d6s to dial down the average damage from 63 (108 max) to 42 (72 max). The next turn, you get 6 of those dice back as the recharge. Now, you have options: another 12d6 breath weapon the next round, fire a weaker breath weapon, or wait to recharge more. If you wait, the next round you have the breath weapon back at full strength. You can also throw off a few weaker breath weapons while biding time for a full recharge.
The mechanic is elegant because the power level stays exactly the same.
Since all dragons recharge their breath weapon on a roll of a 5 or a 6, we know they recharge 1/3 of the time. So we take 1/3 of the total breath weapon dice and just add it back turn-by-turn.
The average damage stays the same, but it’s lot less swingy. The traditional rule gives an 11% chance that you’ll get the full breath weapon the first three turns. That’s enough to decimate any party. That will never happen with the dice pool, since the recharge rate is governed.
If you want stronger breath weapons, you can allow the dragon to exceed their initial damage dice when they recharge. Be sure to keep this within reason by installing a cap, or don’t.
While the power level stays the same, your control over the power level becomes incredibly granular. You can dial up or down the power of the breath weapon to ensure that your players feel the sting without putting their PCs at stake.
When the dragon uses its breath weapon, it slowly builds back up over time. The less it uses, the more it has in reserve.
Remember cheating the rule by rolling early so you metagame for the players? Instead, you can telegraph the information in-world. Show the party that the breath weapon is fizzled out by blowing a little smoke ring the next round that does 1/3 the damage (or less).
Conversely, if you don’t unleash the full breath weapon on the first round, a later stronger breath weapon can really shake the players. It’s a nod to the classic “this isn’t even my final form” trope.
You could argue that this requires more work than the random recharge. But, that depends on how you run it.
I keep my fistful of breath weapon dice behind the screen and I can freely account for this by moving available dice in and out of the pile. This could also be played to great effect in front of the players, depending on your group. To do this, leave the rolled dice on the other side of the screen and take back the appropriate amount at the beginning of every round.
If you don’t keep a pile of dice (or even if you do), it’s easy to account for the available dice on the same scrap paper you’re using to track initiative and HP. You add the same number every round. It takes no more time than rolling a d6 to see if the breath weapon recharges. So while it may require more accounting, it does not require more work.
Although, if you really like rolling dice, you can roll to see how many d6s you recharge. There’s always someone out there who wants more crunch.