RONAs and monsters

This entry is part 16 of 34 in the series Mazes and Monsters

From watching the Mazes and Monsters movie, we’ve managed to glean a lot of the rules: adventure structure (a maze with a single end boss), a spell system (spell points), and a handful of races, classes, monsters, spells, and items.

We’re almost ready to hammer our Mazes and Monsters rules into a complete game! But before we publish, there’s a couple of tiny rules we need to figure out.

Notably missing: AN ACTION RESOLUTION MECHANIC and A COMBAT SYSTEM. All the times that Tom Hanks stabbed a pretend lizard, we never got the needed play-by-play from a Maze Controller. How hard would it have been to have Jay Jay voiceover, “The lizard rolls an 11! He misses! Tom rolls a 4 on his counterattack!”

Today let’s work on the Action Resolution Mechanic. We’ll save the combat system for next week.

For reference, here’s Iglacia the fighter’s character sheet. We can refer to this as we work out our rules.

click for larger version


So far, we know that most actions are resolved by rolling exploding d12s and trying to hit a target number called a RONA (Roll-Over Number for Accomplishment). We are using a somewhat peculiar exploding-die mechanism: rolls of 1-10 are treated normally, while 12 is a critical success (add 10, roll again), and 11 is a critical failure (originally, I said that you rerolled and subtracted your new roll, but let’s simplify it to “subtract 10, roll again).

We also know that characters don’t have numeric stats: Iglacia has “courage”, for instance, not “courage 12”. Therefore, we probably don’t use a D&D-like system where stat bonuses are added to a die roll.

Let’s say a character with the Courage trait is trying to make a skill roll against a magical fear effect. She should get a bonus because of her Courage. We could give her a, say, +2 or +3 bonus to her roll; or we could let her roll 2d12 and take the better of the two rolls, which comes out to about the same thing. The advantage of rolling twice is it almost doubles her chance of critical success (rolling a 12) while vastly reducing her chance of rolling a critical failure (rolling an 11).

By the way: here’s a new product that we should market! FUDGE has its own dice. M&M should have its own dice too: d12s with 1-10 marked normally; one face marked with a fumble symbol (a skull perhaps); and one face marked with a critical success symbol (a star, perhaps, or a grinning Hanks head).

OK, so we have a pretty good system so far: characters roll 1d12 (or the Maze Controller does, actually; characters never roll any dice), or 2d12 if they have an applicable trait that can help. They generate a number that’s between 1 and 10, or higher or lower if they roll an 11 or 12. What’s the target number (RONA) they’re trying to hit?

First, we should do a little math. What are the odds of succeeding at various RONAs, from 1 to 10?

WITH ONE DIE (a person with no helpful traits):

1 92% (1 chance of failure, on a roll of 11)
2 82% (2 chances of failure, on a 1 or 11)
3 73%
4 67%
5 59%
6 50%
7 42%
8 33%
9 25%
10 17% (2 chances of success, on a roll of 10 or 12)

WITH TWO DICE (a person with a helpful trait)

1 99+% (you’d need to roll 11s on both dice to fail)
2 97%
3 94%
4 89%
5 83%
6 75%
7 66%
8 56%
9 44%
10 30% (of the 144 possible dice combinations, you succeed on 42 of them)

The number 6 seems like a good place to start. An unskilled person has a 50% chance to succeed at such a check, while a person with an applicable trait has a 75% chance. Let’s make that our average RONA number, used for most tasks, like attacking a monster of the character’s level.

9 is also fairly interesting: an unskilled person has 1 chance in 4 of making such a check, while a person with an applicable trait has almost an even chance. Let’s make that a Hard RONA check, for tasks like sweet-talking a Giant Dragon.

Similarly, an unskilled person has 3 chances in 4 of beating a 3, while a person with an applicable trait, with a 94% chance of success, is almost assured of success. Let’s make that an Easy RONA check.

(By the way, I don’t assert that Rona Jaffe, or any old-school game designers, did any number-crunching like this while writing rules: only that the good games were those that accidentally ended up with playable rules.)

Gaining Levels

I think our RONA system works well for level 1 characters. Should these numbers scale with level? I don’t want to start adding D&D4e-style level bonuses willy-nilly, but there should be some way that characters improve with level, while higher-level monsters and challenges become more difficult.

Let’s take a look at Iglacia’s character sheet. She appears to have 5 traits. What if you start the game with one trait and gain them as you level? Iglacia could have started with Strength at level 1 and gotten a new trait at every odd-numbered level, finishing up with “Hear through walls” at level 9. Thus, she hasn’t become stronger as she leveled up; she’s become more well-rounded.

What about monsters? It makes sense that RONAs imposed by monsters become tougher as the monsters become tougher. A level 1 Bandit Sorcerer might trap you in a Thought Labyrinth which requires an Easy RONA to escape, while a level 9 Voracian Wizard might trap you in a Cage of Illusion which requires a Hard RONA.

Without having figured out the combat system, we can’t quite design monsters yet, but we can guess that a level 1 monster has all Easy RONAs; a level 10 monster has all Hard RONAs; and the others are in the middle, maybe having a mix of challenging and simple RONAs. Tentatively, let’s set monster-design guidelines for every two levels:

Monster level RONAs
1 all Easy
3 mostly Easy RONAs, with one Medium
5 mostly Medium RONAs
7 mostly Medium RONAs, with one Hard
9 all Hard RONAs

Critical Success and Failure

We have an exploding die mechanic, but it doesn’t do anything yet. A die roll, normally 1-10, can explode to become 11-20 or even 21-30, but since the highest RONA is 9, there’s no benefit to rolling higher than a 10. We need crit rules.

Let’s say that if you beat a RONA by 10, you have a critical success, and if you fail by 10, you have a critical failure. If there’s no bonus or penalty for critical success/failure explicitly built into the rules, the Maze Controller may determine an appropriate reward or punishment for the party. An appropriate reward might be the gaining of an extra clue or a magic item or spell; a punishment might be an extra combat or a false clue that will lead the party into danger. (Remember, the Maze Controller makes all die rolls, and need not show them to the players. If the party gets a bonus clue, they may not know whether it was due to a critical success or failure.)

Because exploding die rolls can reach any number, it might happen that characters achieve a double crit (beating the target number by 20 or more) or a double fumble (failing by 20 or more). Because these are so uncommon, their effects should be spectacular. A double failure leads to the worst possible outcome (often death for the character), and a double success leads to the most triumphant possible outcome (perhaps instant success in the current encounter, or the discovery of a massively powerful item).

Example: A Holy Man is trying to convince a Sprite to give him information about the maze (a Medium Rona of 6). He rolls a 12 on his die roll (“add 10, roll again”). His followup roll is 7, for a total of 17. He’s beaten the RONA by more than 10, which means that he has a critical success! The sprite not only provides a map, but joins the party!

Now let’s see how these rules work in an example scenario!

A Holy Man, Fighter and Frenetic come upon a massive obsidian door! On the door is a control wheel, rusted stuck.

The Holy Man tries to turn the wheel. The Maze Controller decides that it’s a Medium RONA (6) and rolls a die for the Holy Man. The roll is a 4: the Holy Man cannot turn the wheel.

The fighter steps forward. “With my great strength, I turn the wheel,” she announces. The Maze Controller notes that she is using her Strength trait and rolls two dice for her. He rolls an 8 and an 11. That 11 could result in a critical failure if rolled on its own (“subtract 10, roll again”) but, since the 8 beats the Medium RONA, the Fighter manages to turn the wheel.

The obsidian door grinds open. Behind it is a stone statue holding a stone flute. It says, “Best my music to pass!” It then plays a mournful tune on the flute.

The Frenetic steps forward, swinging his lute from behind his back. “Using my Perfect Pitch, I play the same tune, but better!” he cries. The Maze Controller knows that this is a Hard RONA (9), and rolls two dice for the Frenetic because of his Perfect Pitch trait.

The rolls are a 2 and a 12. The 12 roll explodes (“add 10, roll again”); the follow-up roll is a 3, so the Frenetic’s final roll is a 13. Quite good enough to beat the statue, but not good enough for a critical success. If the follow-up roll had been a 9 or higher, the Frenetic would have had a Critical Success, and the statue would have granted him a boon: his lute would have become a magical Lute of Confidence, granting all allies the benefit of the Courage trait while it was being played.

Next week: We’ll figure out the combat system!

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5 Responses to “RONAs and monsters”

  1. sniderman says:


    Very, VERY nicely done.


  2. Jeff Rients says:

    This is some great stuff. Keep up the awesome work!

  3. […] pretty much gotten a complete RPG out of Mazes and Monsters, and now we're putting together the final pieces. In a total reversal of […]

  4. […] Next time: Polishing up the rules! […]

  5. Matt says:

    I want to play this. Better than D&D by far. So quirky.

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