Power Skills in Zenith-3 (and elsewhere)
A ‘Power Skill’ measures how adept a character is at pushing an ability beyond its normal limits. These are rules for handling them, from my Zenith-3 System, and adapting them to other game systems, permitting their application to D&D class abilities and Feats and so on. Useful in any genre with unusual abilities.
Image by Tashi Kongma from Pixabay
What Is A Power Skill?
A Power Skill is the skill of using a power or ability in ways beyond the straightforward applications given in the applicable rules. The More of their capability a character has invested in the power or ability, the more adept they are at using it in different ways. A character can start with just the one ‘trick’ and expand their repertoire as they gain in power.
The Zenith-3 Rules
The rules system used by my Superhero campaign (1982-) have gone through multiple iterations over the years.
- v1: 1982: 18 pages of handwritten amendments to the official Champions Rules. One of the initial changes was to go to a d20-based set of mechanics instead of the Hero System’s original 3d6.
- v2: 1982-1984: Expanded to 20-odd pages typed on a manual typewriter by the sister of one of the players. The first draft consisted of post-it notes attached to both a copy of the official rules and a photocopy of the v1 rules. Also incorporated the official Champions 2 and Champions 3 rulebooks.
- v3: 1985-1986: Supplementary notes that built on the v2 rules but didn’t change much; most of the changes were to power and skill descriptions from the Hero System. In this period, a comprehensive game physics was written and provided to players for the first time, and there were a few skills and powers revised to accommodate it.
- v4: 1987-1989: Added some new powers and skills and redacted some old ones, generally aimed at ‘tightening up’ overly broad skills by splitting them into two smaller ones. More notable now for the general principles, which attempted to create a coherent skills structure for the first time using the concept of ‘dependencies’. Most of these incorporation of these principles was never completed.
- v5: 1989-2000: I now had a Commodore-64 and some word-processing software to go with it. That soon became a C-128. The rules were now printed by an actual computer printer, for which I had to write my own device driver, triggered by codes that I could embed in the documents. This was the first attempt to transition to a fully-self-contained game system, based on Champions 3rd Edition. It ran to over 800 single-sided pages in 5 volumes, two-columns (mostly), and was never finished – but enough was done that it was playable. Introduced the concept of Hybrids – subsystems that were partially one thing and partially another – initially restricted to things like Running. Those page were completed in about a year-and-a-half, and remained the basis of the campaign for 11 years.
- v6: 2000-2001: An aborted effort to compress, compact, and complete v5 while incorporating the accumulated errata and revisions from 11 years of play-testing. By now, I had a laser printer and a windows-98 PC. Some concepts were carried forward into the next edition wholesale, some were further compacted, and some were flagged for deletion because testing showed that they didn’t work as they should in practice.
- v7.0: 2001-2002: A co-writer came on board by uttering the immortal words, “It will only take three or four weeks”. A huge amount of progress was made in this year-and-a-half. For the first time, it was segregated into individual files, one for each chapter and appendix In fact, we were working on the appendices and only had one chapter of skill descriptions outstanding. Notably, the system foundation switched from d20 to d%.
- v7.1 2002-2003: Revision of some powers & disadvantages concepts that didn’t quite work as hoped and correction of errata. Started on the skill descriptions. Most of the contents were completely unchanged from v7.0.
- v7.2 2003-2005: Addition of some new powers, new disadvantages, and more skill descriptions, plus more inclusion of errata and corrections. A complete overhaul of the three frameworks – Magic, Psionics, and Martial Arts. Most of the content was completely unchanged from v7.1.
- v7.3 2005-2006: More errata, more revisions, more clean-up and replacement of things that weren’t satisfactory. Most of the content was unchanged from v7.2 but almost 1/3 of the documents had been revised from v7.0 through accumulated revisions. Stayed stable for about 3 years.
- v7.4: 2009-2012: More errata, more revisions (including a significant revision of the core concepts of the Magic framework, and discarding of the ‘Contacts’ system). But it was a bit more comprehensive than the revisions of previous iterations. There was a lot of effort to find an eliminate ‘infinite points generators’ from the rules – something we thought had been achieved with version 7.2.
- v7.5 October 2010-2026: In October of 2010 it became apparent that it was possible to push the mechanics too far, and that the points costs for some things needed to be changed. I set about analyzing the situation, discovering that the same power could be under-priced, correctly priced, and drastically overpriced, all at the same time, depending on the combination of modifiers and prices, respectively. Ultimately, it was shown that this was a rounding error from a process simplification. Dozens of analysis graphs were prepared like the one below, and a complete top-to-bottom revision of the fundamental concepts began. This mostly consisted of removing that simplification, but after the deep-dive into prices that its discovery engendered, I also ended up discarding the notion that all things should have the same price at all power levels. Instead, progressive costs were introduced for things other than skills, especially stats. I also took the opportunity to incorporate some changes that the players had been asking for, like shifting the minimum score in skills to 0. The adoption of this iteration of the rules remains incomplete; for the most part, we’re still operating on a hybrid of v7.4, with some revisions, and some incorporation of v7.5. While unstable, this hybrid remains playable. But the change is so substantial, I’m cobntemplating renaming this to V8.0.
First Question, having noticed the problem: How significant was it? Answer: Very. I had hoped that it would resolve into a single curve, which would make correction simple. It didn’t.
Second Question, how pervasive was it? Answer: Very. 90%-plus of prices were incorrect through enlargement of rounding errors.
Third Question, how significany was it at a practical scale? Was it being exaggerated in high-price purchases. could it be ignored at lower levels? Answer: Not really – not by enough, anyway. The ‘chord’ where prices are correctly calculated is really obvious in this graph – as is the fact that it’s a very small percentage of the whole.
Fourth Question: Continuous plotting, connecting each data point to the next, was great at showing the overall shape, but implied data that wasn’t really there. Since there was an obvious set of patterns that didn’t fit a simple curve, switching to individual data points would be more useful in trying to understand the pattern.
Fifth Question: Could the problem be isolated / simplified by reducing the values of a single variable? Could a formula be derived that way? Was there a pattern? Answer – there was a pattern – but it’s structure varied with all five variables. In other words, it was systemic; the whole technique was flawed. I would never be able to look at ’rounding errors’ quite the same way again!
The Concept of Power Skills and first efforts
The concept of power skills was introduced in v5 of the rules, but virtually nothing was done about implementing that concept until v7.1. The roots of the concept can actually be traced further back, to v2, and the idea of ‘pushing,’ which enabled characters to spend Endurance to boost the effectiveness of a stat or power, either buying more of it temporarily or overcoming a limitation placed on it by sheer effort.
Between this initial idea (which worked) and the formal mention of Power Skills in v5, I began to feel that it was too easy, that there should be some sort of skill in using the power against which the character should have to roll in order to push that power beyond it’s normal limits.
From that seed, the idea grew that this same skill check would permit the character to use their basic ability in all sorts of tricky ways – bounced shots, some combat tactics, and so on. V7.0 had included, for the first time, rules structured in such a way that skills could also be pushed.
First efforts at implementing the idea went no further than the drawing board, because some fundamental issues remained unsolved: What should the skill cost and how fast should it improve? Should everyone have it, or should it be an ‘optional extra’ that a character had to buy? Or should they get some of it for free but have to pay for the rest? And how much should they pay? Should the expenditure reduce the END cost?
Debate went back-and-forth, with positions adopted, revised, and reversed. When it came time to actually bite the bullet and draft some rules, I deliberately chose a relatively simple solution with some of these proposals to be listed as optional rules or options for future consideration after seeing how well the simple proposal worked in play.
Power Skills In Other Systems
My rules weren’t the only ones to adopt similar concepts. I don’t think that any of these played a role in shaping what my rules became, but thought it worth actually mentioning these. Feats from 3.x are a more likely influence.
Burning Wheel (2002)
“Ugly Truth” allows a character to manipulate social situations to an extreme degree, or use “Intimidation” to completely break a target. I heard about Burning Wheel when it came put but have never read the rules.
GURPS Powers (GURPS 4e Supplement) (2005)
“Power Parry” and “Power Stunts” allowing for exceptional combat feats that transcend standard melee attacks.
D&D 4e (2007)
Similar to Daggerheart, “Powers” permit significant alterations to combat conditions and the like. I never played or read the rules for 4e; I was still transitioning to 3.5 at the time, and the negative press and edition wars made me reluctant to spend the money for a copy.
Powered By The Apocalypse (2010)
This is a game design framework that has been the foundation for hundreds of Indie game systems. “Moves” or “Actions” function similarly to power skills by focusing on dramatic, genre-specific, high-impact actions rather than mundane tasks. I had never heard of it until I started doing background research for this article.
Forged In The Dark (2017)
An SRD used as a foundation for other RPG systems. To date, there are over 300 systems based on these standard mechanics, which derive from the Blades In The Dark rules set (2015-2017).
Daggerheart (2025)
“Power Cards” or utility powers are used to give characters, particularly martial ones, more engaging and specialized options beyond just moving and attacking.
The V7.4 System
Power Skills are defined in the same way as other skills in the campaign. Excerpting them for this presentation has bypassed all the explanations that go with that standard approach, so I’ll have to explain them as I go along.
Such explanations will be boxed off, like this. I’ll try to keep them to a minimum.
Let’s start with some fundamentals:
Skills are bought with Skill Points, enabling the subdivision of a single character point into smaller (and hence more flexible) pieces. All prices given within the skills system are in skill points (SP) unless otherwise stated. These Skill Points are purchased with character points, and are used to both buy and improve skills.
How many skill points you get for a ten-character-point investment (purchases are usually made in blocks of 10) – is determined from General Aptitude. If characters purchase less than the full block of 10 character points worth, they get a -1 on the Skill Point Conversion and round the fraction down.
4.9.1 Ex-cathedra Commentary
The concept of Power Skills coalesced from four directions simultaneously. I was looking for a way to reward characters who invested a lot of character points in a given power, and at the same time I was looking for a way to encourage characters to think about using what powers they had in different ways. I was also looking for a mechanism that would describe how effectively characters had mastered what abilities they had bought. And, finally, there was the existing concept of “pushing” a power, which should not be automatic, but should require a skill roll of some kind. All of these contribute towards character consistency and focus, encouraging characters to become singular masters of a single related ability instead of buying everything under the sun – thereby leaving more scope for unique individuals within the rules.
The concept of each power having an associated skill which would permit the character to express the power in different ways first arose during initial work on the d%-based skills system, when considering better ways of representing a flying character’s ability to do barrel rolls, immelmans, etc, initially inspired by the techniques and rules provided for ad-hoc spell use. This would define the various flight maneuvers as tasks with an associated base difficulty, which could then be used as the basis for an appropriate skill check. The approach appealed because it would be equally applicable to stukas, B52s, hot air balloons, and flying characters – only the difficulty would change. The idea was expanded on further consideration, prompted by recollections by Graham MacDonald of some of the ways in which Force fields could be used – frictionless surfaces, simple shapes for grabbing things (a-la Green Lantern), ball bearings, etc, and by similar expansions of capabilities by other characters in the past, such as Ian Mackinder’s use of the “Earthquake Special” attack with Titan’s STR.
It was originally thought that most of the power skills would be reflections of existing skills, for example EDM (Extra-Dimensional Movement, including Teleport would be analogous to Warp Physics, and that the character would get a number of skill points towards the purchase of the appropriate skill free with the purchase of the appropriate power. This plan did not survive however; in some cases there were too many appropriate skills, in others there were no appropriate skills, and in still others there were skills that seemed appropriate but which just didn’t work on closer examination.
And so, the current, less-defined, more flexible system was created, in which each power has it’s own unique Power Skill. Ordinary skills may be complimentary to the Power Skill (see Skill Use below), and (when appropriate) the Power Skill may be complimentary to a more traditional skill – thereby reflecting the benefits a character gets to his understanding of Warp Physics from his many EDM journeys. But each power has a skill all its own.
4.9.2 Basis
All power skills are based on a specific single Characteristic or Skill Roll, and are treated as Fundamental or Expert skills based on the Base Cost of the power per level.
Skills are d% based. Each stat converts to a characteristic roll to permit saves vs STR, for example. Some of these are referenced frequently in play, some are quite rare. The suffix “#” is used to distinguish characteristic score from saving roll, so CON refers to the stat and CON# to the roll. The stat rolls generate Aptitudes, which are ‘the potential for skills’ – there are 15 of those.
The Aptitude scores are then used to generate actual Fundamental skill values. This approach means that you can improve a stat without having to recalculate dozens of skills; all that changes is the cost of improving aptitudes, saving a few points off the cost of the stat improvement.
Skills are broken down into Fundamental and Expert skills. The two major differences are (1) The Fundamental Skills are a fixed list; and (2) Expert skills are based on Fundamental Skill scores. There are generally 3 Fundamental skills per Aptitude. There are also user-definable Advanced Expert Skills, but we don’t need to worry about those.
Skills range in value from -80 to +150. “Average”” works out to be -12. A skill of 0 or better is enough for the owner to qualify for a job using the skill; a skill of 20 or more is having a professional qualification in the skill, or the equivalent. There are ten ‘ranks’ of characters, from pathetic normal (not called that) to mega-deity (not called that, either), with various grades of Paranormal occupying three of the middle grades. Each caps skills to a different maximum and adds or reduces the cost of skills; the scores quoted in this paragraph relate to Veteran Paranormals, one step below Demigods.
The choice is a matter for assessment by the referee and of the creativity of the character. In some cases, the Basis will be obvious, in others it may require some thought by the character’s creator.
The examples illustrate how the appropriate choice of Basis adds to the definition of a power – the above are 4 different interpretations of HKA. What was previously justification and explanation of a power now has a real impact on the description of the power and what can be done with it.
It is expected that characters will tend to play to their strengths – a character with a high stat will normally have powers that are derived from that stat in some way – but specious logic will be frowned upon. Just because a character has a high stat is not a good enough reason for power skills to be based on it.
When no compelling case is made for any other choice, it is presumed that the basis will be INT#, reflecting that the character’s ability to use the power in different ways is dependent on his ability to work out how to use it in those different ways.
Skills are also classified into subcategories – A-F for Fundamental Skills, G-J for expert skills. These designate sub-tables within the system – lower is cheaper and easier to learn and generally gives more skill ‘bang’ for your buck, higher is more expensive, harder to learn, and gives a lower score.
4.9.3 Classification Code for Base Value
This is determined by the base cost of the power per level. Note that codes A-E indicate that the Power Skill is treated as a Fundamental Skill when necessary and F-J indicate that it’s considered an Expert Skill.
<5 A
5 B
6-10 C
11-15 F*
16-20 D
21-25 G
26-30 E
31-35 H
36-40 I
41+ J
* Use the F column under “Expert Skills”.
EG: Telekinesis has a base cost of 15 points. It would use the “F” column of the Expert Skills table to determine the Base Value of the Power Skill. A character with a Basis of 15 would therefore have a Base Power Skill of 5%.
4.9.4 Base Cost
This is always 0 for a Power Skill.
4.9.5 Free Improvement
Each power has a “difficulty of learning” value given in the table below, based on how flexible the power is and how difficult it is to adapt the basic power to some exotic usage. The character gets 1 skill point worth of improvement to the base value for every 2 character points in the power’s Net cost.
The costing for powers has been broken into the application of modifiers in two stages, compared to the Hero System’s one. “plus” and “minus” modifiers get applied to the total base cost first, and yield Active Points Cost, which is used to determine the END cost of using the power. The formula is
Active Cost = Total Base Cost x (1 + total “plus modifiers”) / (1 – total “minus modifiers”).
The Active Cost is then adjusted by “times modifiers” and “slash modifiers” to get the Net (or Actual) Cost:
Active Cost = Total Base Cost x (1 + total “times modifiers”) / (1 + total “slash modifiers”).
These are normally summarized with math symbols – “+1, -2, x3, /4”. Most modifiers contain only a single type of modifier value, but there are a few rare ones with both an Active and a Net contribution.
I’m not going to quote the whole list, just the first dozen or so entries.
Ablative Armour b
Aid d
Armour b
Change Environment g
Characteristics –
Clairsentience d
Cosmic Awareness f
Damage Reduction d
Damage Resistance c
Danger Sense d
Darkness b
Density Increase b
Desolidification e
EG: A character has bought 80 points worth of Telekinesis. Assuming the character had a basis of 15, giving a Base Power Skill of 5%, that would give them 40 skill points worth of improvement in the Telekinesis Power Skill. Consulting the table above, TK (Telekinesis) has a code of “d”, so finding 40 points worth of improvement on the “d’ column in section 4.7.1 gives +40, for a total skill of 45%.
Click the link to download
I’d love to include the actual tables here that the above example is using, but Hero Games imposes a four-page limit to the presentation of House Rules. I’m skirting close to the limits already, even assuming these explanatory interjections don’t count.
What I can do, I think, is to provide those tables in a PDF.
4.9.6 Maximum Improvement
Power Skills cannot be improved by more than +75%, as shown on the improvement table.
4.9.7 Costed Improvement
Characters can improve Power Skills using skill points like any other skill. The “free improvement” amount does not count as improvement for the purposes of determining the cost of such purchased skill, but DOES count against the +75% improvement limit.
EG: Our character with the 80 points of TK and 45% TK Skill wants to buy an extra +35% for his power skill. Looking up the table in 4.7.1 shows that this costs 35 skill points. Since 40*+35=75, this is the maximum that the character can buy in improved Power Skill.
* From the earlier part of the example.
Purchase Restriction
You cannot spend more additional skill points on a power skill than you get free.
EG: In the case of our Telekinetic, he can’t buy more than 40 skill points worth, or +40. Since the purchase he has made, +30, is less than this, the purchase is fine.
Lost Points
The downside of buying additional improvement to the Power Skill is that the points are “locked in” once play begins. That means that if the character buys additional power, raising his free improvement, any points expended in a purchased improvement are lost. Purchasing additional power skill should be perceived as a bootstrap to give the character a desired level of flexibility before the character has sufficient points to invest in the power level actually desired.
4.9.8 Reduction Of Power Skill Scores
It’s unusual to do so but characters can reduce their power skill scores in the same way that they buy improvements. However, any such reduction is considered a permanent reduction in the base power skill, so even a later improvement in the power skill, or the purchase of additional power, leaves the character with a lower net Power Skill, and the maximum improvement in the power skill becomes +75 from the reduced value. This is useful for simulating powers that the character wants to have under only marginal control.
Whenever the character chooses to reduce power skill scores, they should also suggest (in writing for future reference) a story arc that permits the character to “buy back” the reduction. The referee can schedule or rewrite this plot arc as he deems desirable, but cannot force the character to pay off the reduction.
In other words, the referee can’t run the scenario until the player wants him to, but he can wait as long as he wants to thereafter. These restrictions are designed to prevent characters taking advantage of the rules to buy extra ability and then paying off the limitation before it has a chance to bite the character.
Now we get to the meat of the rules, the parts that will matter the most to readers.
4.9.9 Default Use Of Powers
Each power description should include a default use of the power. This must be as basic as possible (while retaining the special effects that flavor the power and the appropriate consequences of any advantages and limitations) and is the effect that takes place (if any) when the character fails a power skill roll. Some powers have these largely predefined.
EG: Our continuing TK example: “Default: Push the target aside with full STR” (normal attack).
4.9.10 Routine Use Of Powers
Anything that is a default or obviously-straightforward use of the power will usually be declared a “Routine” use of the power. This is anything at the “aim and fire” or “just pull the trigger” level. The referee will usually not require a roll for such uses of the power unless the character’s power skill is extremely low (score less than 0) before the difficulty modifier.
4.9.11 Congruent Powers
It is possible for a character to have two or more variations on the same power. When this happens, they have the choice of declaring the variations as “Congruent Powers” or treating them as separate.
When powers are Congruent, the “free points” are determined by adding 1/2 the net value of the most expensive power, 1/3 of the net value of the next most expensive, then 1/4, 1/5, and so on. This is a compromise between assuming that the additional variations contribute fully, with NO expertise overlap between the two powers, and assuming 100% overlap (which could penalize characters for focused concepts). Both powers use the same Power Skill roll. The higher classification code (the one closest to “A”) is used for determining both Base Skill Values and improvement costs.
“Force Field” and “Force Wall” are considered eligible for treatment as Congruent Powers.
4.9.12 Elemental Controls
Skipped as irrelevant to most readers.
4.9.13 Multipowers
Skipped as irrelevant to most readers.
4.9.14 Spellcasters, Psis, and Martial Artists
Skipped as irrelevant to most readers.
4.9.15 Gadgets
Gadgets, by definition, are ad-hoc constructs, ie the character has minimal skill in using them for any given purpose. These are always treated as per the basic system, but there’s no point in listing the relevant skill because the device is here today and gone tomorrow. That’s why it’s always better to give the gadget to someone else who has skills in the relevant area than using the gadgets yourself. HOWEVER, in terms of CONTROLLING the gadget, the referee can choose to permit the use of a “Control – Gadgets” skill based on the cost of the gadget pool in character points.
This is in contrast to FOCI which are gadgets bought more-or-less permanently using character points, in which the character gets a skill based on the net cost of the Focus or 1/4 the ACTIVE points, whichever is higher.
An exception to these rules are vehicles, which are controlled using the appropriate driving / piloting skill, regardless of the vehicle’s cost to the character.
4.9.16 Congruances With Framework Elements
It is obviously possible for a character to have a “normal” ability and an element within a framework that are congruent, eg a character could have an EB (Energy Blast) and a separate EB that is in a multipower or elemental control or whatever. Where this is the case, use the appropriate “modified” value for the power in the framework as a congruent value to stack with the power outside the framework.
EG a character has a 100 point EB and a spell that cost 6 character points, on which he has listed a 20-extra-Mana cost. The spell is therefore worth a net “value” of 46 points for the purposes of determining skill level in the power; but this is treated as congruent to the 100 point EB. The characters “free” skill with EBs is 1/2 of 100, or 50 points worth, plus 1/3 of 46 which equals 16 points (rounding in the character’s favor), for a grand total of 66 points worth of “free” skill.
Author’s Note: This is a complicated situation that I hope never arises in real life but feel that sooner or later it’s sure to come up….
Planned Expansions in v7.5
4.9.17 Specialties
Characters will be able to buy a specialty in a specific use of a Power Skill, for example “Trick Shot”. This costs the standard amount in Skill Points for such a specialty as though the skill were the same as any other, and gives +30% to the use of the power in that way.
4.9.18 Expert Versions
For powers rated A-E, once the maximum improvement has been achieved, characters can choose to purchase an Expert Version of the power skill with GM approval. Such approval will only be given if the character has made extensive use of the Power Skill in play. The expert skill has a base level of the skill achieved in the Fundamental Skill version and permits improvement of the skill by another +75%.
The process is as follows:
1. The code transitions to the code 5 higher – A to F, B to G, C to H, D to I, E to J.
2. Consult the purchase price table looking in the appropriate column for a base skill of 1/2 the indicated level.
3. The indicated price is the cost of +0% in the “Expert Version.”
4. The same code is cross-referenced with the desired improvement in the Expert Version to get the price of the improvement.
5. Improvement purchased is added to the existing skill score.
Purchasing the Expert Version reduces the level of difficulty for maneuvers by one step – ‘Routine’ becomes ‘Easy’, ‘Difficult’ becomes ‘Routine’, etc., in addition to permitting further increases in skill level. This makes extremely difficult or complex maneuvers more achievable and less complicated ones more reliable.
Task Difficulty
There’s no section number on this section because I cut out a whole truckload of stuff not relevant to power skills – and what’s left starts off in mid-section.
Task Difficulty is the GM’s response to the question, “How hard should this proposed action be, under ideal conditions”. It sets a baseline modifier. That then gets adjusted progressively to take into account the differences between “ideal conditions” and the actual circumstances in the field.
Task Difficulty Table
Trivial task +100
Routine task +50
Easy task +25
Moderately Difficult task +0
Difficult task -10
Very Difficult task -30
Extremely Difficult task -50
Almost Impossible task -75
Absurd to even try -100
“Permission Denied” -120
Environmental Circumstances
Environmental circumstances are usually rated on a +50 to -50 scale, but extreme cases may call for plus-or-minus more than that. A positive modifier indicates a more ideal environment, a negative modifier indicates a handicap. It is generally easier to rate the suitability of the environment from 1-10, multiply the result by 10, and subtract 50, but the technique employed is left to the referee’s best judgment.
Action Modifiers
Third, the referee should assess anything else the character is, or has been, doing, that might improve or lessen the chances of success. This includes any modifiers from combat maneuvers. These are generally rated on a +25 to -25 scale each, and in general there will be no more than 1 or 2 of them. He should also assess and include anything else about the character who is making the check that is relevant, which includes Aiming (refer Chapter 12 Combat), Complimentary Skills (see below), Specialties, etc.
Target Modifiers
Fourth, the referee should assess anything the target is, or has been, doing, that might improve or lessen the chances of success. This includes any modifiers from combat maneuvers being performed by the target, movement, etc. These are generally rated on a +25 to -25 scale each, and in general there will be no more than 1 or 2 of them. He should also assess and include anything else about the target that is relevant, for example the size of the target relative to the range +([size/range-1] x 25), in inches (one inch = 2m).
Range Modifiers
Fifth, the referee should apply the appropriate range modifier. This is normally the standard range modifier given in chapter 12, Combat, but this can be modified by advantages and limitations on powers, etc.
Anything Else
Finally, the referee should apply anything else that’s applicable. There generally won’t be anything, but it’s worth a moment’s thought to double-check.
The Total
The total should then be determined (assuming the referee hasn’t been working that out as he went along) and, if necessary,adjusted to fit within the absolute limits of ±150 modifier. The referee need not announce the exact modifier, simply the closest “category” to the total – taken from the same Task Difficulty scale given above.
EG: If the modifiers total +35, the referee need only announce that it’s a “Fairly Easy” task (Easy = +25, Routine =+50).
4.14.5 Power Skill considerations when designing Powers
In the old days, what mattered was getting your power for the fewest possible points. The less you spent on something, the more you could spend elsewhere.
Well, the old days are gone. The Power Skill system rewards focused characters with flexibility and ability.
In the past, it was enough to decide how much of something you wanted to have – an RKA that was so big, Flight that was this fast, and so on. Then you tried to afford all these abilities. With the advent of the power skill, it is now just as important, or even more so, to decide how much you want something to cost. There is a benefit to NOT reducing the END cost, and it has to be weighed and compared with the benefits of doing so.
When designing powers, the definitive question is now “What do you want to be able to do with it?”. Power Levels and Power Skill levels are both necessarily defined by the question. Are there any defined standard maneuvers that you want to be able to achieve? The difficulty, and resulting chance of success may well be the defining issue for the power.
In Practical Terms
1. Powers have a base rating according to how much a minimum level costs. You look up that rating on a table.
2. Next, you decide the skill basis of the power. This is usually a stat roll, but can be a skill roll if a sufficiently convincing case is presented.
For example, St Barbara’s Flight is based on her Acrobatics skill rather than her Agility, because she literally uses aerial acrobatics for sharper changes of direction. The downside is that she has to shut her power off for a round to do so. For most characters this would be a massive restriction but because she is literally an Olympic Gymnast with skills to match, St Barbara gains massively in the accuracy of her flight maneuvers and the likelihood of success in them compared to most characters. This also feeds verisimilitude – this “stop, reorient, re-start” approach is probably closer to how a character with that background would fly.
3. Cross-referencing the score in the Basis with the classification code gives a base score in the skill.
4. Next, you find the power itself on a list for it’s improvement code, and cross-reference the net cost of the power with that improvement code to get the amount of free improvement in that base score that has resulted from spending more than the minimum on that power.
5. The maximum improvement in the power skill is either determined by subtracting this ‘free improvement’ from 75%, or by doubling that free improvement, whatever is LOWER.
6. Another table using the same codes can either yield the cost of that much improvement or the amount of improvement for a given cost, whichever is more useful.
Adaption To Other Systems
Until the shift to the d% based system, skills were rated on a d20 scale. To facilitate characters being adapted from the old system, or from standard Champions / GURPS, this section listed approximate equivalents.
What’s interesting is that this is a two-way street, providing an opportunity to adapt the mechanics provided for D&D or whatever. Even if you only use this system when your existing mechanics don’t cover whatever a PC is trying to do, it can be useful to have this in your back pocket.
As a guide, the following are a list of approximate conversions from the d20 scale to the new d% scale:
1 = -80
2 = -71
3 = -64
4 = -57
5 = -48
6 = -41
7 = -34
8 = -25
9 = -18
10 = -11
11 = -2
12 = 4
13 = 12
14 = 20
15 = 27
16 = 35
17 = 43
18 = 50
19 = 58
20 = 66
21 = 73
22 = 81
23 = 89
24 = 96
25 = 104
26 = 112
27 = 119
28 = 127
29 = 135
30 = 142
31 = 150
The same conversion scale can be used for the Official 3d6 Champions System. However, it should be noted that it is now much harder to get higher scores; it also recommended that before conversion, the old score be reduced by 2 to give a more realistic target.
EG: A character used to have Acrobatics 18/-. In the new d% system, that’s equivalent to an Acrobatics skill of 50%, but a more realistic figure to aim for in character conversion comes from converting 18-2=16/-, ie 35%.
But, if you want to go further, or your game mechanics are neither d20 nor 3d6-based (Traveler, I’m looking at you), there are two essential translations that you will have to make; everything else will flow from those.
Skills Extremes
I you look at the tables provided in the attachment, you will find that the highest base skill value is 100, and there’s a maximum improvement of +75 to that. And a specialty can get you another +30, if it’s relevant. So the highest possible skill to have is 205.
What is the highest skill possible in the game mechanics you are using? If it’s open-ended, use 3x, 4x, or 5x the highest roll result. So, for Traveler, that’s 2d6 -> 12; x3 = 36, x4 = 48, x5 = 60. One of those three numbers will be the maximum.
The absolute minimum that you can usually have in a skill would appear, at first glance, to be zero – but in the realm of roll conversions, that’s misleading. Remember the -2 suggested for 3d6 conversions? That’s because 3d6 have a minimum roll of 3, and both d20 and d% have a minimum roll of 1. You have to ‘pin’ the adjustment to the same foundation.
Let’s pick a hypothetical 4d6 system and derive a conversion to a basic d%.This consists of a mathematical formula of the form, d% = md + 4d6r x (Md – md) / (M4d – m4d).
Looks complicated. But it gets a lot simpler once you realize that defining the system basis, you’ve defined everything in that formula as a constant, so that you end up with something that reads, d% = ## + 4d6result x ##.
md = minimum roll on d%, Md = maximum roll on d%, m4d = minimum roll on 4d6, M44 = maximum roll on 4d6. What we’re trying to match is the range of variability.
So: d% = md + 4d6r x (Md – md) / (M4d – m4d)
= 1+ 4d6r x (100-1) / (24-4)
= 1+ 4d6r x 99/20
= 1+ 4d6r x 4.95.
It’s almost certainly close enough that you could use 4d6r x 5.
Here we have a range of -80 to +150 and a conversion target of whatever.
But if I were working up such a conversion for my own use, I would actually break the results into two bands – one less than average human and one more, simply because the Zenith 7.4 rules bias that value low to make little more room for skilled individuals.
Basis Decision
Once you have the ranges, the next decision to be made is what you’re going to base the ‘free base competence’ on – in other words, how much skill are you going to give the characters for free, and how are you going to measure the answer?
Both the Zenith 7.4 rules and the Hero System from which they derive are point-buy systems. Everything is under the control of the player. That’s not the case with other systems, where stats may be rolled, not chosen.
I urge GMs to get creative. For example let’s pick a class ability from D&D – just about any version will do. It first becomes available at, say, level 8, and is based on a character’s STR score.
As a basis for a skill in “using that ability,” i would look at 8+STR score. I might add multipliers to change the relative importance of each contribution and bring the STR scores closer to the range of the aptitudes used in this system to set skill levels, that’s up to you.
Improvement Cost & Quantity
The third design parameter also deals in the points-buy question – how much does it cost to improve the skill, and how much improvement should you get for that expenditure?
Difficult Decisions
And finally, you have all those decisions that were so hotly debated about the philosophical underpinnings of the system. Really, these boil down to one simple-to-state question: Does everyone with the relevant ability get some or all of the Skill that goes with it, or is this something extra that they have to buy or obtain somehow?
Again talking about D&D for a moment, I can envisage a whole range of magic items – tokens or badges or rings – that do nothing but unlock “Prowess” in a particular class ability.
I had to focus in on this system because the adventure that I’m working on will give one or two of the PCs some difficult challenges in using specific powers – and neither of them have the Power Skill scores for those powers written down. So I will have to calculate them.
And there wasn’t enough time for me to do that AND write a post for Campaign Mastery. This, on the other hand, was 70% copy-and-paste. Nevertheless, the more I worked on it, the more I realized the value of the premise of the article – this IS something that should be more widely available for GMs to consider. It IS valuable as a concept and as a technique outside of the Zenith 7.4 rules. And therefore, this is NOT a filler post – which is what I thought it might be, when I started it.
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February 28th, 2026 at 5:33 pm
[…] to which this system was actually put. This purpose ties in directly to Power Skills, which is why last week’s post had to precede this one – they make a 1-2 […]