How the collective fascination with Nat 1 and Nat 20 disregards the rules (5e)
Updated: Aug 1, 2020
There's a unique thrill that comes with rolling a natural 1 or 20. The shared hype of a high damage critical hit. The party's dismay at failing a crucial check so spectacularly. It's a key part of Dungeons and Dragons and other d20 game systems. So much so that the internet-at-large is flooded with fanciful tales of critical successes and failures. Some folks learn of the mystical natural 20 before they learn anything else about D&D.
I'm not great at math. Or probability. Or numbers. But I am certain of this: the probability of rolling a natural 1 on a d20 is the same probability of rolling a natural 20. To broaden that, there's a 5% chance of rolling any given number on the d20. We're equally as likely to roll a 1 as we are a 10, 15, 18, or 20.
So what makes a Nat 1 or Nat 20 special? Nostalgia, and not much else.
The worst a d20 can roll is a natural 1. The best a d20 can roll is a natural 20. Everything in between is a varying degree of bad, mediocre, and great. A 19 is great but painfully close to 20. A 2 is terrible, but at least we dodged the Nat 1 bullet.
Except, in Dungeons and Dragons 5th edition there isn't a Nat 1 bullet to dodge. Unless the character is rolling death saves, in which case that's one helluva lethal bullet. Too bad they can't take the Dodge action while bleeding out on the ground.
Rules as Written (RAW) there are two instances in the Player's Handbook (PHB) regarding "Rolling 1 or 20" and they are the following:
Rolling 1 or 20 Sometimes fate blesses or curses a combatant, causing the novice to hit and the veteran to miss. If the d20 roll for an attack is a 20, the attack hits regardless of any modifiers or the target's AC. This is called a critical hit, which is explained later in this chapter. If the d20 roll for an attack is a 1, the attack misses regardless of any modifiers or the target's AC.
PHB, pg. 194 | Combat
Rolling 1 or 20. When you make a death saving throw and roll a 1 on the d20, it counts as two failures. If you roll a 20 on the d20, you regain 1 hit point.
PHB, pg. 197 | Combat
If we look at the Dungeon Master's Guide (DMG) there is another, optional, rule of interest:
CRITICAL SUCCESS OR FAILURE Rolling a 20 or a 1 on an ability check or a saving throw doesn't normally have any special effect. However, you can choose to take such an exceptional roll into account when adjudicating the outcome. It's up to you to determine how this manifests in the game. An easy approach is to increase the impact of the success or failure. For example, rolling a 1 on a failed attempt to pick a lock might break the thieves' tools being used, and rolling a 20 on a successful Intelligence (Investigation) check might reveal an extra clue.
DMG, pg. 242 | Running the Game
That's it. RAW, in D&D 5e there are only two cases where rolling Nat 1 or Nat 20 has any special effect. Three, if we count the optional variant. Yet, lots of tables house rule that a Nat 1 on an ability check or saving throw is a critical failure, and a Nat 20 is a critical success. Sometimes this is compulsive. It just happens. Nat 1s and Nat 20s are just so darn cool and satisfying. The bowstring snaps mid-attack, the NPC stumbles and falls off the 100ft cliff, the evil spy divulges everything they know to the interrogating party, and so on and so forth. It's fun and memorable when crazy good and crazy bad things happen, against all odds.
It's also a throwback to 3.5e, with its variant rules for "Critical Success or Failure" and "Critical Misses (Fumbles)." These variant rules across editions bleed together into a collective, shared understanding of what Dungeons and Dragons should look like. Often without taking the time to understand why or how we got here and if we even should be here. New Dungeon Masters, or DMs coming from other editions, have a preconceived notion of how a natural 1 or natural 20 should play out. Often without actually reading or knowing the official D&D 5e rules. And that ignorance can have dramatic effects on the table.
A natural 1 can turn an ordinary skill check or saving throw into a critical catastrophe. It can be lethal. It can get a player character (PC) killed in a ruling that goes against RAW. We'll delve deeper into this in the merciful medicine check later. Likewise, a natural 20 can fluster the DM. Suddenly the impossible is possible! The plot is accelerated by the players thwarting the Big Bad Evil Guy's (BBEG) plans five sessions earlier than intended thanks to a critical success on a d20 ability check!
Note that the 5e optional ruling merely suggests increasing the impact of a success or failure and does not suggest auto failing or auto succeeding. The wording goes out of its way to say "on a failed attempt" or "on a successful check." This implies a natural 1 can and should still result in a success if the DC is met after adding modifiers. Likewise, a natural 20 can be a failure if the DC is higher than 20 + the applicable modifiers.
Yet, DMs and players are eager to let RNG shift the narrative. Because it's entertaining when the goblin rolls a 1 and drops its sword on a critical fumble. It's goofy when the fighter tries to climb up a cliff, only to get stuck three feet up and fall on his butt. And it's empowering when the natural 20 Charisma (Intimidation) check sends enemies running in fear for their lives.
It's less fun when the roll has meaningful consequences. When the character is highly proficient in a skill, yet a natural 1 overrides their hard-earned competence with an unsightly blunder. It's character ending when the monk is bleeding out on the ground, two failed saves in, and the well-meaning barbarian does a Wisdom (Medicine) check... and rolls a natural 1.
The takeaway isn't that DMs should be forbidden from implementing critical success and failures. More important is that the DM and players need to first understand RAW and collectively agree that house ruling critical ability checks, saving throws, and fumbles is fun and fair.
P.S. There's a fascinating history behind the rise of natural 20 and critical hits in tabletop gaming that I'd love to touch on another day.