Thursday, October 1, 2020

Random Events

A random event or “random” is an idea I’m borrowing from the MMORPG RuneScape, although it may exist in other contexts or games also. I thought I’d see what I can learn from the design of RuneScape generally, and this is where I’m starting.

What is a Random Event?

RuneScape is an MMO with heavy repetitive elements. Where there’s repetition, there’s the opportunity to automate, so pretty quickly it was overrun with bot accounts farming resources, getting in the way of other players, and distorting the economy. Random events were an early anti-bot measure: whenever you’re doing stuff, there’s a chance that something strange happens. For example, if you’re chopping down a tree, maybe that tree is actually an ent right now, and if you keep chopping it will break your axe.

Maybe you were just running around, and a talking cat (“Evil Bob”) imprisoned you and asked you to play a minigame for your freedom. Sometimes a drunk dwarf appears and wants to share his kebab with you, but if you ignore him too long he’ll start attacking. You might find when you’re burying bones, that you disturb some existing grave site, and a shade attacks you.

These events were removed from the game as more effective anti-bot strategies were devised. However, a fork of RuneScape (Old School RuneScape, or OSRS) only includes updates that are voted on by the community, and after some revision, random events are still a significant part of that game.

My working definition of a random event will be: “a specific, rare, and unforeseen event that has some chance of resulting from a routine activity, and which demands immediate attention.”

“A specific…”
Random events are pre-defined. This could be considered a limitation of a computer game because it’s common enough to improvise exact rare circumstances in tabletop games. But the limited stable of random events means they have a different feel.

“rare and unforeseen event…”
A random event has to be rare enough that you can’t “farm” it or plan around it. Sometimes you can get a message in a bottle while fishing, but you don’t go fishing for one. Explosive gas might damage your pickaxe, but not often enough to bring two pickaxes.

“…that has some chance…”
My intuition is that they should not be more common than critical hits/failures (5%), and should probably be less common.

“…of resulting from a routine activity…”
In their current state in OSRS, most random events are truly random. They just happen whenever or wherever you are. This is something that computers can do great, but in a tabletop game, it would be tedious to check every combat round (say), for a range of infinitesimal chances that something utterly unexpected might happen. So we will use the older model of random event that happens when you are doing some specific, usually repetitive task.

“…and which demands immediate attention.”
A rainbow is not a random event. If we are going to go through all the work of checking for randoms, we’re going to make them impactful. In RuneScape, this is either because the event will cause you harm, grant you a reward, or literally remove you from your previous situation.

Random Events in D&D

In many ways, random events already exist in D&D. Consider random encounters while travelling: they may not strictly meet the definition above, but they come close. Critical successes might also come close, especially with some sets of house rules, but again fall a little short.

I think the closest thing to them in D&D “canon” as I know it is probably the divine interventions in Deities & Demigods. If you’ve never had the pleasure, Deities & Demigods is a mess of a book. Its purpose is unclear, it has questionable ties to its source material, and the information in it isn’t organized in any meaningful or useful way. Maybe it says something though, that I got rid of my AD&D core books, but never parted with this one.

These are the most promising random events I could find in it:

Action Chance Result God (page)
A believer is reanimated. 2% per level of deceased Arawn appears and fights against the reanimation (75%) or offers a substitute dead person (25%). Arawn (p. 26)
An original composition is sung during battle.1 5% The singer is granted a bonus level for the duration of combat. Brigit (p. 27)
A believer flees from battle. 0.5% The deserter is struck dead. Morrigan (p. 29)
An original composition is performed/spread by others. 1%/5% Great wealth is given to the creator by the lord of the hold, in the form of gold. Oghma (p. 29)
An evil act affects more than 500 people. 0.05% The evildoer is given a disease-causing gift. Lu Yueh (p. 40)
Hastur’s name is spoken. 25% Hastur sends 1-4 byakhee to slay the speaker. Hastur (p. 45)
A tomb with Anubis’ image/consecration is robbed. 5%/10% Anubis appears to kill the robbers. Anubis (p. 50)
A cat is killed. 0.1% Bast either kills the slayer or demands half of their remaining life in devotion. Bast (p. 50)
A character takes a great risk. 5% The gambler is gifted a luck stone. Bes (p. 51)
A good person seeks righteous revenge. 5% All of the avenger’s ability scores are increased to 19 until the deed is done. Horus (p. 51-52)
Someone creates a new magic spell or item. 5% Isis gives the creator a charm to resist the effects of one spell. Isis (p. 52)
Someone/a worshipper/a cleric creates a device that is highly useful. 5%/10%/15% Ptah gives the creator a Thet, an amulet that either allows you to become ethereal once/week, or acts as a one-way anti-magic shell. Ptah (p. 53)
Dryads are in danger/Men are attacking the forest. 1%/5% Mielikki appears to aid her dryads/attack the woodcutters. Mielikki (p. 60)
A believer is reanimated. 1% Tuoni comes to reclaim the resurrected soul. Tuoni (p. 61)
Someone accomplishes a particularly difficult task. 5% Epimetheus gives the person a ball of magic clay that can form itself into any 4th-level creature. The creature then fights the person (60%) or serves loyally until death (40%). Epimetheus (p. 68)
Hermetic arbiters accept a bribe or graft. 15% Hermes punishes the corrupt arbiter. Hermes (p. 71)
A lawful-aligned person breaks an oath. 1% per level of oathbreaker Varuna causes them to be punished. Varuna (p. 79)
A being takes an unusual and great risk (in combat). 2% The gambler makes all their saves and attack rolls for the combat. Kishijoten (p. 82-83)
Beings that are neither lawful nor chaotic dig deeper than 100 ft. 5% Darnizhaan attacks the diggers. Darnizhaan (p. 88)

New Random Events

The interventions in Deities & Demigods are interesting, but mostly still fall short of our definition. For example, many of the activities are not “routine”, and many of the effects are still left up to the GM. So if we want to make our own randoms, let’s start with “routine” activities in D&D (assuming 5e). Skill checks come to mind first,2 so for each skill, we’ll define one event that could happen whenever that skill is tested.

Now you’ve done it. Whether through quick motion or tense concentration, you’ve slipped into the plane of shadow. You can exit anywhere you like, but the further you go the less accurate your exit will be.

Animal Handling
The king of the cockroaches is impressed by your empathic abilities. Would you be so gracious as to carry him and his retinue back to the outdoors or into the nearest structure? For this noble service, the king will grant you a knighthood! Knighthoods from the king of the cockroaches are not worth much, but are technically valid. Should you kill the king of the cockroaches, insectoid assassins will be sent for 1d6 nights following, but the new king does not bear a grudge.

That thing you never quite figured out, you know the one? It just clicked. If you can find writing tools and drop everything you’re doing for the next 10 minutes, you can create a spell scroll of a random spell.

Koroibos appears in a flash of lightning! Nude, oiled, muscular, he challenges you to a footrace. If you accept he insists on racing right now on the nearest suitable course (a hallway, for example). He wins and loses graciously, but gives one who defeats him an olive branch. When broken, the branch summons him to assist in one task (during which he automatically succeeds on any Athletics checks). In any case, he leaves in a similar flash of lightning.

I knew it, and this confirms it! Thou art that same villain! I demand satisfaction immediately! Whatever deception was just practiced, the duelist now believes that the character is responsible for the death of one of his twins, and fights to the death.

Whatever knowledge you called forth was an affront to the dead. They demand you retract any statement made, or fight to the death (again). If beaten, the answer to one historical question can be extracted. Nobody else can see the shade in question.

You understand the true nature of all things, and it is as though space and time stand still. Except for you, and if this was an opposed roll, the opposition. You both have enough time to speak a few sentences or take some decisive action (one “combat” round) before the rest of the world catches up, and after, nobody else will know.

You’ve caught the eye of Maxavogg, a lesser devil. He thinks you’ve got potential, kid. But you gotta learn the basics, review the fundamentals. Tell you what, he’s got a free seminar on the subject, take this card and burn it if you want to try. The seminar is 24 hours, but you’ll come back proficient in Intimidation if you weren’t already, and you’ll be known to a handful of [falling] stars in the infernal org chart. He won’t leave until he’s shaken everyone’s hand. (Thanks, Ancalgon_TB.)

You find a tiny blue cog. These things just turn up sometimes and nobody knows why. Still, rich people collect them.

Look, Ariel the djinn really meant to study for their mortal anatomy class, but they just didn’t get to it. If you could answer a few questions for them, they could definitely do quick favor for you, say a quick spell or sow some confusion somewhere. The questions are bizarre, but simple enough to answer. If Ariel is ignored, they might steal something shiny before disappearing.

Isn’t there a children’s rhyme about that lichen over there? “Purple fur and orange leaves / Death the drinker’s soul recieves” Maybe that wasn’t it, but you certainly recognize it. Given 10 minutes’ uninterrupted work, you could probably get a useful dose of poison from it.

One of the fair folk is hiding a cache. If you stand perfectly still and silent for the next 10 minutes, they won’t notice you’ve seen them and you can retrieve it after they leave.

A talent agent was in the audience (in the shadows if necessary), and would like to offer you a considerable advance. If you accept, 1d4 fiendish lawyers attack the next time you perform the same song again.

An impressionable dandy is not only persuaded by your arguments, but by your very lifestyle! They loyally follow you around, loudly agreeing and generally being obnoxious. If any sort of combat breaks out they throw one attack at random before fleeing. Left outside of your powerful presence, they quickly grow bored and disappear.

Clarence, a neophyte angel, needs to help some more good people before he’s allowed into the choir. Will the characters swear they’re really very pure of heart? (Clarence trusts them if they do.) That’s just great, is there anything he can do for them that doesn’t involve direct or indirect harm? Oh, uh, maybe not that big. Huh. Maybe like, he can carry a message or something? When this negotiation is finished, Clarence carries out the task unfailingly, but if no task can be settled on, he’s quite huffy and the character takes disadvantage on their next roll.

Sleight of Hand
No trickery escapes the watchful eye of Constable Dogberry, and that certainly looked like trickery. If you agree to cooperate he’ll issue you a very official looking, if incomprehensible … ticket? Court summons? It’s hard to say. But he’ll be detaining you for the next 10 minutes at least while he writes it up. Put up a fight and well, … Dogberry will probably flee after any amount of damage is dealt.

You’re so sneaky! You’re practically invisible! Recall though, that Invisibility has duration of 1 hour. Good luck!

The hunter has become the hunted! For the next 24 hours, King Herla will hunt the character (sans the entire wild hunt, this is his day off). He can be defeated in single combat, or dissuaded by a boring hunt, but if a quarry evades him for the duration, he gifts them an antler. When broken, the antler summons him to assist in one task (during which he automatically succeeds on any Survival or Nature checks).


Tying randoms to skill checks has a lot of potential. Whenever a player goes to roll, they roll a d% alongside, and on a 000, the random event happens. Only rolling when there’s a risk of failure prevents “farming” the events, and rolling multiple dice adds excitement.

Special consideration should be given to group checks. As they exist in D&D now, each member makes the check. To keep randoms rare, they should only be checked on individual tests, or alternative rules for group checks should be used. Similarly, they shouldn’t occur on passive checks.3

Because these events are so rare, they must be applied consistently. Even if the athletics check happens in an anti-magic field, the laws of the universe governing Koroibos’ appearance allow him in and out regardless. Religion checks don’t involve any action on the character’s part, but they can still attract Clarence.

These definitely aren’t ready to use as-is. Adversaries need stats, chases need rules, quizzes need questions, and wishes need limits. In the spirit of the original random events, the difficulty of any challenge should probably be scaled to the character that caused it, so that the event is always “relevant”.


The events I sketched out here would fit a high-magic gonzo setting, but I do think some version of the mechanic could be worked into other settings. Even though they occur rarely, they define a setting by the types of unexpected things that occur. And because they have a chance of occurring to anyone, you can lean on them elsewhere in the setting. The cockroach court can be involved in unrelated intrigues, and the impressionable dandy might show up later following some NPC.


Random events speak to a kind of story-telling that is rarer in 5e, but more common in OSR games, where the story is largely emergent. Even given some larger plot, a random encounter or roll on a table can recontextualize elements of it unexpectedly. These “story wrenches” still appear in 5e, but the reaction to them is largely negative from what I can tell (consider the wild magic sorcerer, for example).

At the same time, tying them to skill checks is a type of rules maximalism that the OSR does not usually go for. It would be easy to forget to check for these events, especially if there are any quantity of these always-in-play-but-seldom-relevant rules. One possible “clean” solution might be to hook them into a VTT, owning the video-game roots of the idea.

Personally, I think these challenges will stop me from using the idea in its current form, but it was a fun thought experiment, and I think the seed of the idea could be useful.

1 As written, the player needs to sing an original composition for the whole of combat. Like I said, it’s a weird book.back

2 Cantrips come to mind second, which could be a different, but promising avenue to explore.back

3 I’d have to remember to use passive checks more often, to avoid perception having all the fun (or not).back