Looking for feedback on homebrew magic system


Homebrew and House Rules


I am making an entire game system. I have a magic system in place for it but I would like some feedback on what you all think of it. Criticisms (of the constructive sort), comments, suggestions, and alternatives are all welcome.

The magic system.

This is part of a skill based system which has skills and features (features are like feats, perks, etc).

To learn magic one picks a spellcasting feature. Each one is a magic tradition, such as Wizardry or Sorcery, and affects how easily spell effects of each school are to learn and cast.

Once a magic tradition feature is gained, the mage can learn a spell effect as a skill. Since each spell effect is a skill, once learned they can be improved like any other skill (skills improve through use).

Casting magic has two elements to worry about, complexity and fatigue cost.

Complexity determines how difficult the spell is to cast, the higher the complexity the higher the casting DC.

Fatigue cost is how much fatigue is spent when the spell is cast.

The ability to change the number of targets or the range of the spell requires no skill or learning, but instead alters the complexity and cost of the spell. For example, casting fire in a small cone has a lower fatigue cost then casting it as a large burst.

I.E. Freya casts a spell to make a fireball. She rolls her Evocation (Fire) skill. She is is using her Wizardry magic tradition.

The complexity, or DC, for the spell is 14 (10 base for Wizardry Evocation effects, +2 for ranged burst, +2 for long range)

The fatigue cost is 9 (4 for evocation, +4 for 20' ranged burst, +1 for long range)

Freya rolls her skill and if she rolls higher then the spell's complexity, she is successful in casting the spell and reduces her fatigue by the spell's fatigue cost, however, if she rolls high enough, the fatigue cost can be reduced.


Skill-based magic systems have been done in a variety of forms and fashions in several iterations of d20. All of them have the same problem: skills scale differently than DCs and skill-based feats throw off or trivialize the DC calculations.

How are you accounting for this in your system?

Don't get me wrong, I'm not trying to disuade you. I do, however, suggest you not refer to them as skills. Make them a new category "traditions" or whatever you want. Allow them to select a number based on what you envision (whether they gain points at certain levels they can spend or some other method) and you now have complete control over any and all things that modify your magic "skills".

Edit: by the way, looks fine at first glance, but I'd like more information (DC modifiers for traditions, the feats or perks you mentioned, and so on).


First, this is not d20.

Skills are not set numbers, but rather a skill is a dice and higher skill is a larger die (similar to savage worlds).

The features grant access to certain skills.

Skills come in different tiers, easy skills start higher, while difficult skills start lower. The cost to increase is based on how many times the skill has been increased rather then the die size, thus upgrading a difficult skill from d4 to d6 costs more then upgrading an easy skill from d4 to d6.

When a skill is rolled you also roll a luck die and an attribute die, thus making a bell curve which scales differently then d20.

It is also designed for DCs to remain the same throughout, DC 40 is the max achievable by real life humans, above that is superhuman (which many fantasy games delve into). Thus DCs don't scale up based on character "lvl," they are set markers. Indeed this game doesn't have character levels at all.

The game isn't as unfriendly to large "lvl" differences either, with progression focusing more on expanded options rather then skyrocketing bonuses. Thus scaling is very different than d20. Yes a character could specialize and focus on one skill, but by the time they have a single d10, others will likely have d6s in tree to five skills.

Just like E6 keeps progressing by expanding options and gaining feats without ever increasing the DC and CR zone, this game is similar.

Edit: I call them skills because they are treated exactly like skills.


The basic spell schools,
School Cost Complexity
Abjuration 0 0
-Conjuration +1 +3
Divination -1 0
Enchantments -1 +6
-Evocation +2 0
-Fate 0 -3
Illusion 0 +1
Necromancy +3 +6
-Transmutation +1 +3

The Wizardry and Witchcraft features allow a character to train in magic effect skills. The tier of these skills are based on the feature. These features do not affect the DCs directly beyond the initial base. The base DC is here, because it is easier to set them differently for different settings, I.E. the Misting and Allomaner features for magic in the Mistborn setting would have a much lower base DC (in case you are unfamiliar, it requires consumption of metals and one normally must be born with it rather then learning by study).

Wizardry
Base DC 10.
Tier 0 (these skills, by school, start at a D4)
Fate Effects

Tier 1 (these start at a D2)
Evocation Effects
Transmutation Effects
Conjuration Effects
Illusion Effects

Tier 2 (these start at a D0)
Abjuration Effects
Enchantment Effects
Necromancy Effects

Tier 3 (these start at a -d2)
Divination Effects

Witchcraft
Base DC 10.
Tier 0 (these skills, by school, start at a D4)
Fate Effects

Tier 1 (these start at a D2)
Enchantment Effects
Necromancy Effects
Illusion Effects
Divination Effects

Tier 2 (these start at a D0)
Abjuration Effects
Transmutation Effects
Conjuration Effects

Tier 3 (these start at a -d2)
Evocation Effects


Nymitz wrote:
First, this is not d20.

Ah. While I have high system mastery/knowledge with d20, not so much with your custom system as I don't have the time to devote to the development of something from the ground up. learn all the ins and outs and nuances of your system, etc.

Sorry I can't be of more help.


If you are looking into a non-d20 skill based magic system you could look at GURPS for guidance since they are a heavy skill based system without levels. I know I have read a few d20 books with variant magic systems, but they are rare and I can't remember any of them off the top of my head.

Sorry.


Gurps is some weird complicated mess (as near as I can tell from the couple of books I attempted to read) but it seems to be some sort of percentage system.

What I have here is a system that rolls dice and adds them together for a total that is then compared to a DC. In that sense it is similar to d20.

It differs significantly from d20 on the leveling and classes, or lack thereof.

The issue Da'ath pointed out was a leveling issue, since most d20 systems have levels and adjust DCs based on those levels. The scaling issue doesn't apply.

I like keeping the DC scale rather then percentage, as it is simpler overall, and easier to tell how well one did in an objective sense. It also allows for different scales of power to be used seamlessly, such as deities, superheroes, and mundane people, all on the same scale without adjustments, and one can instantly see how they compare.

So in that way d20 can be applicable. I guess you could say it is very similar to d20 except stripped of classes and scaling.


I think this could all theoretically work pretty well. Fatigue is essentially an mp system with--I assume--some kind of penalty for going under certain thresholds.

The viability of this system is entirely dependent on how you design your spells and skill checks and what-have-you. It sounds like you have a mess of math problems on your hands here, but I don't think that should dissuade you. Just take the statistics seriously and this system should work fine. And remember all of the levers you can pull: DC, fatigue cost, and the way skills and fatigue amounts themselves level.

I am curious though: does your system have die in between 12 and 20? Or die over 20?

I feel like the DCs of your checks are sorta impossible.


DCs The DCs are scaled such that DC 40 is about the highest acheivable in the natural tier (which is what real life people can do), going higher than that is possible for characters that are beyond real life humans.

So contemporary settings will likely only use the natural tier and thus would almost never have DCs of 40.

But fantasy settings with fantastical beasts, lycanthropes, deities, etc will likely go above that and have higher DCs.

Thus how impossible the DC is really depends on teir of the characters.

The natural tier is dice sizes up to d8. So Einstien was an elite specialist in Knowledge (Science [Physics]), so could roll a d12 (luck) + d8 (int) + d8 (science) + d8 (physics) + d? (Circumstance bonuses) for 38+

Enhanced tier goes up to d12. For up to DC 48+

Supernatural tier goes up to d16 for DCs up to 60+

Divine goes up to d20 for DCs up to 72+

Dice The dice steps are each even number. When online this can be handled as easy as any other dice size. Around the table, dice can be "split" and rolled as multiple smaller dice, though they together count as one die for mechanics. I.E. a d14 can be rolled with a d6+d8.


Oh wow. This is actually very similar to my own homebrew system then. I am actually super surprised (though my game is about magic lazer cowboys).

I also like that you apparently have skill groups (like physics belongs to science, right?). As a note though: "splitting" your die actually increases the expected value of a roll by .5 and decreases the variance. As such, your "split" d14 is a much stronger improvement from a d12 than a d12 is from a d10.

In my own system, I sort of bent over backwards to stop that from happening.


As it is a bell curve already, the effect isn't as bad as would be for individual. Also it happens at higher values.


Got interrupted, so...

Since the dice splitting occurs at higher values, it only comes into play at higher tiers and thus is less then 1% shift in the final values. The bell curve becomes a bit sharper/thinner, but by that point it doesn't make much difference.

Critical are handled differently, so the chance of getting near max or min on rolls isn't important in that regard.

Also note, the improvement being larger then unsplit die isn't the bad for two reasons, first, the cost to advance a die rises sharply compared to dnd, specializing is expensive, second, that .5 increase remains that small, it doesn't compound as you go higher, except about once every few tiers. Even deities are wary of someone who has stats that high.


Well, I am more worried about the thinning of the bell curve than you are, clearly, but that is okay. I just really like a wide dispersion because it means that I can confidently take automatic failures and successes out of my game.

But anyways: it seems like your magic will work pretty well. It is just gonna take some tweaking to get it right. Unlike pathfinder, you also have the luxury of adjusting the mechanics for every caster all at once. So spice to personal preference and serve.


Well, thinning the bell curve is what allows players to feel like they are advancing while still allowing characters with a wide disparity in skill level to still be relevant.

I kinda wanted it so a new player could start a "level 1" and join a group regardless of the group's "level." The trick was doing that while still allowing character advancement.

I guess I'll try again at starting a test game this weekend. Hopefully some players will show up this time.


I hope it goes well and I hope you post your materials on here some time. Seems neat.

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