Monster Math: Hidden 5e Encounter Structure

Did forbidden 5e math too. The whole game is fake! Shout-out to Paul Hughes' business card monster manual, and Reddit user Asinus for their calculations on average DPR per character tier.

Basically, I figured out that the game really is balanced around monsters taking around 4 hits or 7 attacks to defeat if their CR equals the party's level. In other words, a medium encounter should take about 2-3 rounds to resolve. This is because monsters' hit points and armor class increases at more or less the same rate as player-characters' damage-per-round and attack bonus, respectively. We can extrapolate that deadly encounters have double the duration.

The damage that a medium encounter deals per round also tends to be 20% of the player-party's total hit points, although it tends to be distributed between multi-attacks and legendary actions for more powerful monsters. An ancient white dragon (CR 20) attacks up to 6 times per turn, each dealing an average of 15 hit points; an ancient red dragon (CR 24) has the same number of attacks, but deals ~20 hit points instead (25% party total). Both have obscene attack bonuses, +14 and +17 respectively, meaning that most of their attacks will hit.

More importantly, however, damage per round matters less than the monster's own longevity. Keep in mind that both of the dragons have 3 legendary resistances, meaning they take 8 and 10 attacks respectively to defeat. That's the difference of 3 or 4 encounter rounds, which by extension is the difference between 60% total party damage (20% times 3) or 100% total party damage (25% times 4). It's called deadly for a reason, isn't it!

This is a major, major point in favor of fudging encounters. The game isn't about defeating monsters but surviving them, so decreasing or increasing the longevity of an encounter to match the expectation that it is (somewhere between) easy or deadly maintains precisely the intended structure of the game. The D&D combat rules turn out as no more than a facade for the superheroic attrition game underneath.