Chart Based Spellcasting

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This post uses a chart that is not obviously reduced down to a simple formula. I say that because you have to give it to Delta. He broke down the Turn Undead table causing me rethink this post. Once you realize that the Turn Undead table is basically rolling 5+ on 1d6, it didn't seem worth presenting the original tweak. It felt like redoing the 2d6 spellcasting class presented earlier.

Where's the fun in that?

Still, I have created a Turn Undead based caster before here. It's not a tweak like my previous posts, but it's there for anyone that wants to use it.

To use a table, the challenge was to come up with a table that was not easily reducible to a simple die roll. After quite a few experiments and lots of research, I attempted to use a drop table or the original FASERIP table.

The drop table is not a bad idea, but my lack of art ability makes this a rather unattractive option. The FASERIP table (and the ZeFRS and 4C variations) were interesting, but it introduces column shifts and basically still feels like a percentage roll. Redoing a percentage roll is too much like another previous post.

So I looked for a chart in any game I have that wasn't so obvious. Despite the fact that it requires custom dice, I ended up choosing Paydirt, the American football simulation game. One reason for the choice was the ability to make something visual within my limited artistic abilities. The main reason was that it was different.

Blah, Blah, Blah, we saw the chart as the featured image.

Using a custom chart means, of course, that I am beyond making small tweaks, but introducing a new mechanic that doesn't exist in any S&W or OSR clone I know. I still plan on using the spell table to be a check on this spellcasters' power, but more on that later.

The link to the chart is here: Spellcasting Paydirt The top row represents the level of the attempted spell. The leftmost column represents the possible dice roll results. Roll the dice, look down the first column for the result and then look right for the level of the spell attempted. Green means success, red means failure. If you choose to use them, purple is a major success and black is a major failure.

Paydirt used some truly funky die. The dice for the chart use the custom dice rolled for offensive plays.

The offensive dice are:
Black die: 1-2-2-3-3-3
White die: 0-0-1-2-3-4
White die: 0-1-2-3-4-5

The Black die was the tens digit and the White dice were added together to get the ones digit. Because of the zeroes, the results range from 10 to 39. When you do the math, the results do not make a simple curve, so looking at the chart does not provide likely probabilities at first glance. Only seven of the twenty-nine cells for a 9th level spell are red or black, yet these are the most difficult spells to cast (about a 50-50 chance). First level spells have eight red or black cells, yet they are the easiest to cast (about a 90 percent chance).

The other appeal of these charts, are that there is some ability to make designs without affecting the odds of successful spellcasting. (If there is interest, I'll make a few.) I thought about using these to represent astrological charts. Let's say a simple die roll (1d6 or 1d8 determined by the number of charts made up) determines which chart is available. The charts wouldn't be too different (although that could be fun, too) but interesting enough that a player is not always trying to roll in the 30s.

Like the other two classes in earlier posts, a spellcaster using this chart is still an unreliable spellcaster. Spells are not guaranteed in the same way as the traditional S&W Magic-User. We could have them make magic items that increase their reliability. We could also have them make potions to guarantee the spell is cast. You can certainly mix and match the special abilities of the previous classes, but let's do something a bit different.

Going with the idea that these spellcasters use astrological charts, let's add in a dash of numerology. At every even level, roll the custom dice to add a magic number to add to the character sheet. Results are cumulative. An 18th level spellcaster would have nine magic numbers. When casting a spell, rolling a magic number results in success. No matter what the result says on the chart (good or bad), rolling a magic number is a standard success, not a major one.

Still, the spellcaster may get no benefit from the magic numbers, even at high levels. Instead of adjusting the XP Chart, we'll add another minor ability, a small hex ability.

This hex ability uses the custom chart to determine success. Roll 1d8 to determine which column to use and roll the custom dice to check the result. A character's magic numbers can also be used to determine success.

On a successful roll, chosen targets within a 20 by 20 foot area are struck with a saving throw penalty for three rounds. If the 1d8 result is 1 to 4, the penalty is -1. If the result is 5 or more, the penalty is -2.

Again, not a tweak, but with a new mechanic, an astrologer or numerologist class with some interesting abilities. Even with the hex ability based on the Prayer spell, it is a class that is still weaker than a Cleric and on par with a standard Magic-User. The choice of a standard Magic-User is still a good one as the M-U always successfully casts whatever spell he or she wants. Want something different? Well, not as reliable, but fairly interesting without being overpowering.

As for a type of magic item that can be found, it could be a gem, a stone, or other kind of object inscribed with a magic word. The word provides another magic number for this class to use on a one-time basis. If you have a houserule that allows all M-U to create scrolls, you can use a similar rule for the creation of these magic words. The cost is 1d8 * 100 gp and take 1d8 days to create. A spellcaster can only use one of these items per spell attempt.

A more powerful magic item cover a group of ten rolls. Specifically, these gematric perfections would make rolls 10 to 19, 20 to 29, or 30 to 39 into successes, regardless of what appears on the chart. The cost of these items would be 4500gp and could be used only once. Unlike the lesser magic item, this expensive magic can be stacked.

In the next few posts, I'll talk about the interchangeability of the four classes and new types of magic items that affect all of them. The goal of this series of posts is a modular system to create interesting NPCs or classes. More soon.

Casting Like a Thief

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The first spellcaster relied on the Swords & Wizardry saving throw. The second relied on reaction rolls, very loosely based on Chainmail. This post will talk about using percentile dice like a Thief using his or her skills. Although I written about it previously, the last post in the series will use the Turn Undead table to determine success.

A simple way is to set a percentile chance of casting spells is to each spell level. Set an 85% chance to cast a 1st level spell and subtract 10% for each level after that. Yes, this means that there is a base -5% chance to cast a 9th level spell; there will be more on that later. The 85% number comes from the Thieves' chance to Climb Walls at 1st level.

To make things interesting, there will be two modifiers to the roll. One modifier will be based on the spellcaster's level, the other based on Intelligence. For each level of the spellcaster, the chance to cast the spell increases by 5%. For example, a 1st level spellcaster has a +5% chance of success while an 8th level spellcaster has a +40% chance of success. As far as Intelligence, a spellcaster with an INT of 15 or more gains a +3% chance of success. If the INT is 8 or less, the modifier is a -3% to the chance of success.

Again, the purpose of these classes is to provide tweaks, not rewrite spellcasting classes, so the spell table is still the main method of limiting this class' power. This prevents higher level spells from being cast too soon as compared to other classes. A 2nd level spellcaster without a spell table limit would have a 85% chance of success to cast a 2nd level spell. For that matter, the same spellcaster has an almost two-thirds chance to cast a 4th level spell. So, the spell table remains the limiting factor.

Despite rolling percentage dice, this class is only slightly less reliable than a standard Magic-User. As such, I think it would be fair that this class would lose a spell slot on an unsuccesful roll. This makes them even less reliable, though the risk at higher levels is still pretty small. a 7th level spellcaster can automatically cast 1st and 2nd  level spells. There will be a 90% chance to cast a 3rd level spell and an 80% chance to use their lone 4th level spell slot. Those odds are still pretty good.

Like any unreliable spellcaster, there's a good chance that he or she will attempt to find ways to guarantee success. The skill-based spellcaster makes temporary foci to guarantee success. The Chainmail(ish) spellcaster uses amulets to gain an advantage to cast a spell successfully. Neither of these classes, however, risk losing spell slots. If the magic focus or amulet fails, the spellcaster can try again, even if they don't have any more magic aids to boost their chances.

To make them different from the other two classes so far, let's have this class strive to save the spell slot, instead of increasing the chances of success. It's easy to think about increasing success as somehow stablizing the magic required to perform a spell or increasing the raw magical power being manipulated. The spell slots, though, measure capacity.

If you imagine a spell as being a semi-living creature crawling around in a spellcaster's skull, saving the spell slot can be compared to a trap that snatches the spell back in case of failure. A different way to think about it would be like the safety on a firearm. The spell has to successfully turn off the safety to be cast, but if not, no spell is used up. The spell is still in the chamber, ready for another try.

Stability still requires a cost, mechanically and financially. I'll stick with the tried and true 100gp per level of the spell slot to be saved. Mechanically, the cost will be a -5% modifier to spell success. The physical representation of the safety could be something ingested by the spellcaster before casting the spell. I have not read Brandon Sandersons' Mistborn series, but if you are a fan, this could be used as a basis to make Allomancers. Instead of metal, the spellcaster could swallow powdered gems, or just about anything else. For ease of reference, I'll call these ingestible items Mnemonics.

So this class has four tweaks:

  • Base percentile chance to cast a spell based on spell leve, modified by spellcaster level and spellcaster Intelligence.
  • If the roll fails, the spell slot is lost unless...
  • ... the spellcaster creates Mnemonics that are consumed so that the spellcaster keeps the spell slot in case of failure.
  • Mnemonics cost 100gp per spell slot level and lower the chance of success by 5%.

All in all, not too bad. Because of the ingesting, it is easy to think of this class as an alchemist. If you allow a standard Magic-User to create scrolls in your game, you should allow this class to make potions of their spells.

Fireball spells can be like dragon's breath, or the tiny bead of energy escapes the mouth, your preference. Charm spells can show themselves as songs (or not if you really really hate bards). There's all kinds of creative ways to have a spell come from a potion instead of a scroll. How about the Magic Jar spell or even the Prismatic Sphere?

Wrapping up, here is a spellcaster that uses a familiar mechanic (rolling percentage dice like the Thief) with two tweaks, that turns out to be a type of potion-making spellcaster. The spells may be the same, but he or she will play differently from the spellbook toting standard Magic-User.

Next time, the Turn Undead table.

Something like Chainmail Casting

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As a player and a referee, my experience has been that for a class to feel different, the mechanics have to be different. Running one (maybe two) games, I appreciate smal changes or tweaks to existing classes to provide a new experience without having to master a new subsystem. In this post, I look at something similar to the venerable Chainmail magic rules. It may be more accurate to say that it is based more on reaction rolls/morale rules. For reference, the first spellcaster in the series (Saving Throw as Magic skill) is available here.

The best summary of the Chainmail rules I have found is here on Jeff Rients' Site. (I don't own DCC, so I can't speak to the DCC part of the post.) Essentially, roll 2d6 modified by spellcaster's level and spell level. If the result is 8 or more, the spell is successfully cast.

Starting with this mechanic, I want to make a small change. Chainmail did not have nine levels of spells and it seems that spell level and spellcaster level were more closely related than D&D. In other words, a 2nd level magic-user could cast 2nd level spells. Even if I am mistaken about it, the mechanic breaks down if I add the spellcaster's level to the dice roll for Swords & Wizardry. Not only that, there are nine spell levels instead of six. So here is my version of Chainmail-ish spell casting for Swords & Wizardry:

  • Roll 2d6 greater than or equal to 7+ Spell Level for success.
  • Half of the Spellcaster's level, rounded down, is added to the roll.

For those that care about numbers, this gives a first level magic-user about a 42% chance to successfully cast a spell. (Roll 2d6 greater than 8 with no adjustment to the roll.)This is close to the odds for the skill-based spellcaster I wrote about. Just like the previous spellcaster, the spell table is used to prevent spellcasters from launching high level spells before the standard magic-user.

Again, should the spell slot be lost for missing the roll? Not for this class. That leaves our 1st level spellcaster more chances to use the only spell slot.

Since the spell table is being used, we're still left with a class that is an unreliable spellcaster and somewhat less than the standard Magic-User class. We could adjust the XP table, but I want to add class features instead.

The skill-based spellcaster is able to make magic items that guaranteed spellcasting success. If I grant that ability here, I've only re-created the same class with a slightly different mechanic. That's too much the same, so let's try something else.

I do want to provide some kind of boost to the chances for casting spells, so let's do it by adding an extra d6 to roll and taking the best two. We'll say that this spellcaster can make astrological charts, leyline maps, or amulets to improve the chances of success. For the sake of convience, I'm going to call them amulets.

This leaves our poor 1st level spellcaster to improve only to a 68% chance, but as he/she advances, it will become much easier to cast lower level spells. A 2nd level spellcaster has an almost 89% chance of success to cast a 1st level spell. A 3rd level spellcaster has about an 81% chance of casting a 2nd level spell.

What this does is allow better chances without providing a static bonus. Even without gaining an extra die, as the spellcaster progresses casting lower level spells becomes much easier. At higher levels, the spellcaster will not need to pay for the ability to cast lower level spell. He or she will instead spend money to cast higher level spells. Specifically, we'll make it similar to last time: the cost of the improvement will cost 100gp per spell level and take the spell level number of days to create.

If a spellcaster spends 400 gp, he or she gets to add an extra die when attempting to cast a 4th level or lower spell. The amulet(or chart or whatever you call it) will only work for one spell regardless of success. In other words, if the spell still fails using an amulet, the amulet is lost.

At this point, we have a standard spellcaster with three tweaks:

  • Roll 2d6 greater than or equal to 7+ Spell Level for success.
  • Half of the Spellcaster's level, rounded down, is added to the roll.
  • Through making amulets, the spellcaster can add an extra die to improve chances of success taking the best two of the three dice as the result.

We're still left with a class with less spellcasting ability than the standard Magic-User class, so what else can be done?

Let's look at the standard Dispel Magic spell in Swords & Wizardry:

Dispel Magic
Spell Level: Druid, 4th Level; Magic-User, 3rd Level
Range: 120 feet
Duration: 10 minutes against an item

Dispel Magic, although not powerful enough to permanently disenchant a magic item (nullifies for 10 minutes), can be used to completely dispel most other spells and enchantments.

The chance of successfully dispelling magic is a percentage based on the ratio of the level of the dispelling caster over the level of original caster (or HD of the monster). Thus, a 6th-level Magic-User attempting to dispel a charm cast by a 12th-level Magic-User has a 50% chance of success (6/12 = .50, or 50%). If the 12th-level Magic-User was dispelling the 6th-level Magic-User's charm, success would be certain (12/6 = 2.00, or 200%).

Let's use this to provide a counterspell ability, but use a different  mechanic to determine success.

Instead of division, I will use subtraction to modify theroll, adjusting the target number by the result. For the examples listed, a 6th level spellcaster attempting to counter a spell cast by a 12th level Magic-User has no chance of success as he or she would have to roll a 13 to succeed. (12 - 6 is 6, add the adjustment to the target number to get 13.) Turned the other way around, the spell caster has an automatic success (the same as the Dispel Magic spell description). To prevent abuse of the power, The cost will be the highest level spell slot available. At higher levels, the spellcaster will likely cast the actual Dispel Magic spell, but unlike the standard Magic-User, he or she can attempt to dispel more than one spell by sacrificing the highest available spell slot available. For lower level spellcasters, this is a bargain, but the chances of success are much lower. Still, this ability is limited by the number of slots available on the spell table.

Looking at the four changes, we have:

  • Roll 2d6 greater than or equal to 7+ Spell Level for success.
  • Half of the Spellcaster's level, rounded down, is added to the roll.
  • Through making amulets, the spellcaster can add an extra die to improve chances of successof spellcasting
  • A counterspell ability that costs the highest level spell slot available.

I imagine this type of spellcaster being a Magic-Eater (similar to a sin-eater). Through a short ritual, these mages have a natural ability to negate magic at a cost of limiting their own ability to wield spells.

Next time, I'll look at a percentage based spellcaster.