Comparative Character Generation, Part 2: An Overview of d20 Systems

Posted: 2006-11-26
Word Count: 5590
Tags: d20 old-stuff rpg

Table of Contents

AUTHOR’S NOTE (2006): I wrote much of this report in previous months, but left huge gaping holes for actual character generation. I have decided to present the “fluff” text, and defer the “crunch” to my next report.


Last time I considered six relatively light-weight, generic, modifiable role-playing systems. This time I’ll give an overview of some d20-based systems: Dungeons and Dragons, Iron Heroes and True20, plus some PDF-only material I’ve found on RPGNow or elsewhere on the internet.

As stated before, I’m examining systems primarily to find the best fit for some campaign ideas I have, and a preferred play style. Some questions for the evaluation:

  1. How long it takes to translate a character concept to a valid character? How complex is character generation? How well does character generation reflect the original concept?

  2. What are each character’s chances of success in a conflict? How long does it take to compute them? Do the results violate common sense or basic physics?

  3. What style of play does the system support: gritty vs. cinematic, story-oriented vs. combat-oriented?

  4. How much tinkering would I have to do to fit my campaign ideas? Are there pre-tested alternate rules that I can borrow? Can I just point to a rulebook and list house rules, or would it be clearer just to write out my own variant of the game?

  5. How complex are the rules? Can a new player or GM pick them up in a few minutes? Hours? Sessions?

  6. Will players have to buy a $40 book, or can they download a free summary from the web? Can they find rulebooks somewhere, or has the game been long out of print?

  7. How much published (or web) material exists for the game? Can I reuse published adventures with little or no modification? Is there an active community around the game?

While some of these these considerations come from the previous report, the nature of d20 requires some modifications.

My Ideas

I’ve mentioned my campaign ideas a few times, so for clarity let me mention what they are:

  1. I have at least four campaign worlds in mind: one modern dark fantasy, another Conan-esque fantasy, one a weird blend of fantasy and steampunk, and another quasi-fantasy with some odd twists. Recently I’ve also had ideas for a “weird West” campaign, and I might recycle some ideas for either a space-opera or hard-science science fiction campaign. So a pretty broad range …

  2. In the fantasy campaigns, I would like magic to be a “background” or subtle force. No fireballs, no walls of steel, no polymorph. Some possibilities:

    • Classic psychic powers like telepathy are the only magic.

    • A magic-user must weave effects slowly in painstaking rituals.

    • All magic requires the intercession of supernatural beings who must be persuaded to work wonders.

    • For every advantage granted through magic, a mage must pay a karmic debt; a huge effect may require a quest.

    • Magic only augments “natural” abilities and effects to a phenomenal degree. Or, perhaps what is “natural” in this would would be magical to us.

    • Magic isn’t what you can do but what you know about the supernatural, and how you can use it to your advantage.

    • Magic is a scam perpetuated by a guild of charlatans using conjuring tricks and human gullibility.

  3. All or almost all player characters would be human, perhaps from different social or cultural classes. Nonhuman races – species, really – would tend to be recurring antagonists, or mysterious and reclusive beings with alien mindsets.

  4. “Monsters” would be rare; the most dangerous creature is man, or at least the more common humanoids. As a corrolary, not every strange-looking creature exists to be riddled with arrows and hacked into sashimi.

  5. Especially in science-fiction worlds, “aliens” and non-humans would be truly alien. They won’t be humans with bumpy foreheads or funny masks and a few exaggerated personality traits.

  6. Science fiction worlds wouldn’t have “psionics”. If psychic powers existed at all, they’d be subtle and unpredictable (much like magic, which is essentially what they are). Think River Tam, not Kimball Kinnison.

  7. Most plots would not revolve around hacking through foes. While every character should know how to defend him- or herself, charm, intellect, and judgment can accomplish as much or more as bulging muscles and unparalleled swordsmanship. There might be forces who could destroy player characters utterly, but a clever person could persuade them to stand aside or even help.

The d20 System

From Wizards of the Coast’s d20 System Concept FAQ:

The company believes that one of the major factors which caused the collapse of the commercial tabletop RPG market from 1993 to 1996 was the proliferation of different, incompatible, core game systems.

The company believes that when many different game systems proliferate in the market, they cause significant problems with the shared rules knowledge and preferences between communities of players necessary to sustain a long-term, commercial market for RPG products.

To jump-start that effort, Wizards of the Coast has created the System Reference Document, and the Open Gaming License (OGL) to allow royalty free, nonexclusive use of the game system at the heart of Dungeons & Dragons by anyone who wishes to do so, for both commercial and noncommercial works.

The d20 System, officially defined in the d20 SRD replaced many systems in AD&D with “The Core Mechanic”: roll a d20, add any relevant modifiers, and determine whether the result equals or exceeds a Target Number. Skill use, combat, and nearly everything else except damage applied to hit points uses this mechanism, much like other modern games.

The trick is, to define the “relevant modifiers” and the “target number”. Modifiers come from characteristic bonuses (or penalties), skill bonuses (or penalties), class bonuses, etc. The Target Number may be 10 + similar modifiers for NPCs (for example, Armor Class or how hard an opponent is to hit), but might be relative to the action contemplated (e.g. climbing a tree vs. climbing a sheer rock face). One advantage of this system is that the Game Master (or Dungeon Master, by tradition), can call for players to roll and keep the actual target number (or opposing roll) secret; he may simply hear or see the final roll + modifiers, and tell the players the outcome.

“d20” is a trademark of Wizards of the Coast, reserved for products that use the d20 SRD in a specifically prescribed manner, notably to exclude rules related to character generation or experience. Other products are said to be OGL compliant. Despite WotC’s disdain for “many different game systems”, a number of companies have created variant rules, such as different character classes, different combat rules, even different ways to handle attributes and skills.


Computing probabilities for a particular action in d20 is trivial: (21 + Modifiers - Target_Number) x 5%. If the Modifiers are at least one less than the Target Number, success is automatic; if the Target Number is over 20, failure is often inevitable without sufficient modifiers. (In some instances, a “Natural 20” is always a success, regardless of Modifiers and Target Number.) Sometimes the Target Number is actually an NPC’s roll, which is equivalent to the probability for 2d20 - 21 + Player_Modifiers - NPC_Modifiers.

Basic d20 Combat

I’ll let the SRD speak for itself:

At the start of a battle, each combatant makes an initiative check. An initiative check is a Dexterity check. Each character applies his or her Dexterity modifier to the roll. Characters act in order, counting down from highest result to lowest. In every round that follows, the characters act in the same order […]

At the start of a battle, before you have had a chance to act (specifically, before your first regular turn in the initiative order), you are flat-footed. You can’t use your Dexterity bonus to [Armor Class, or AC] (if any) while flat-footed. […]

If some but not all of the combatants are aware of their opponents, a surprise round happens before regular rounds begin. […] Combatants who are unaware at the start of battle don’t get to act in the surprise round. Unaware combatants are flat-footed because they have not acted yet, so they lose any Dexterity bonus to AC. […]

Each round’s activity begins with the character with the highest initiative result and then proceeds, in order, from there. Each round of a combat uses the same initiative order. When a character’s turn comes up in the initiative sequence, that character performs his entire round’s worth of actions. […]

In a normal round, you can perform a standard action and a move action, or you can perform a full-round action. You can also perform one or more free actions. […]

A standard action allows you to do something, most commonly make an attack or cast a spell. […]

A move action allows you to move your speed or perform an action that takes a similar amount of time. You can take a move action in place of a standard action. […]

A full-round action consumes all your effort during a round. The only movement you can take during a full-round action is a 5-foot step before, during, or after the action. […]

Free actions consume a very small amount of time and effort. You can perform one or more free actions while taking another action normally. However, there are reasonable limits on what you can really do for free.

An attack roll represents your attempts to strike your opponent. […]

Your attack roll is 1d20 + your attack bonus with the weapon you’re using. If the result is at least as high as the target’s AC, you hit and deal damage. […]

A natural 1 (the d20 comes up 1) on the attack roll is always a miss. A natural 20 (the d20 comes up 20) is always a hit. […]

If the attack roll result equals or exceeds the target’s AC, the attack hits and you deal damage. Roll the appropriate damage for your weapon. Damage is deducted from the target’s current hit points.

There are a plethora of explanations, expansions, explorations, exceptions, special cases, and options that I’m leaving out, but this is the gist of d20 combat.

What About D&D?

The original and most popular d20 system is, naturally, the venerable Dungeons and Dragons, now in version 3.5. Everyone else does it, so why not me?

Well … given the principles stated above, I have the following objections:

In other words, I’d have to hack D&D to the point where it was my own d20 variant. Since I’d rather re-use others’ work as much as possible, I need an alternative.

Iron Heroes


Iron Heroes is a variant Player’s Handbook, for a world focussed on warriors of various types, in uncivilized lands. It takes its inspiration from the Conan books and similar Swords-and-Sorcery tales. Its token magic-using class is dangerous to be around, and the new rules focus on characters who rely on their own talents, not on ever-better weapons and armor.

This fit – actually, inspired – the fantasy world I’m most likely to run, so let’s take a closer look at Iron Heroes.


Except for the Arcanist and the Thief, all characters are fighters of one stripe or another. Each class has a special way of fighting: the Archer concentrates on ranged weapons, the Executioner prefers sneak attacks, the Weapons Master excels at one weapon, the Man-at-Arms learns a variety of weapons and techniques, and so forth.

As an aside, this is the first time the notion of Character Class made sense to me. I still don’t know why a Ranger can’t learn other combat styles or the Cleric has some fighter-like capabilities, but I understand the distinction between a lightly-armored rage-fueled Berzerker and a heavily-armored, stalwart Armiger. It takes years of reinforcing your shield, or chewing on it, to learn each style.

Combat Changes

Iron Heroes alters d20 combat in a number of ways. Here are the most notable:


In Iron Heroes, armor doesn’t add to a character’s “Defense Score” (what the rest of d20 calls Armor Class). Instead, it subtracts a variable number of damage points (e.g. 1d4 or 1d6).

Contrast this to GURPS 4e or BRP, where armor absorbs a fixed number of damage points. The explanation is that the die roll forces players not to rely on armor to absorb hits, and from the Simulationist perspective makes sense if you assume the piecemeal armor of ancient or prehistoric times. (But where does that leave the Armiger?)

Hit Points and Reserve Points

Heroes have an expected number of Hit Points, and an equal number of “Reserve Points” to start with. After a combat, a character can replace lost Hit Points with Reserve Points. If he goes to zero hit points during a battle, however, the usual

Because of the lack of healing magic, this makes sense from a game perspective. The text cites Conan’s ability to shake off the effects of one battle to enter another … which may be true to the genre, but makes the Simulationist in me a little twitchy.

Token Pools

Most character classes, and some skills, use “Token Pools”. Some actions increase the number of tokens in a character’s pool, which he may then use to augment other abilities. For example, an Archer may Aim at a particular target, and time spent Aiming increases an Aim Token Pool against that target. The Archer can then redeem tokens for particular types of trick shots, such as Armor Piercing Shot to reduce armor or Storm of Arrows to fire additional arrows rapidly at the same target.

The Sample Character Sheets include tokens marked with a distinctive symbol to denote Aim Tokens from a Berzerker’s Fury Tokens and all other token types. This could become a bookkeeping nightmare if several Token Pools were in play at once.

Note that Harriers, among other classes, don’t use Token Pools.

Stunts and Challenges

As an extension of a mechanic for Skills, Iron Heroes lets a character accept penalties to an Attack or Defense Roll to achieve some sort of extra effect. For example, for a -2 Attack penalty, you can hamper your foe’s movement by striking at his thighs or tangling his legs.

You can also perform Stunts by describing an attack or defense combined with a Skill roll, giving you a bonus. For example, in the Maneuver Stunt “Improved Speed” you might describe swinging across the rigging of the ship to escape a pursuer; if you make your Use Rope check against a DC of 20, you’d gain one square (5 feet) of distance.

Between these two, a creative player can replicate any cinematic or realistic combat tactic he can successfully argue for.


So far Iron Heroes sounds good, although I worry about having such combat-oriented characters when I’d like to run adventures involving unsolved crimes, exploration, political intrigue, and metaphysical themes.

True20 Adventure Roleplaying


True20 from Green Ronin grew out of their earlier games Mutants & Masterminds and Blue Rose. It’s a more radical departure from stock d20:

There are numerous other modifications, often borrowed from other game systems. True20 attempts to streamline d20 rules, notably combat – you only need a d20 – and provide a more “generic” and adaptable system. The hardback and recent PDF include four game worlds, one Arabian fantasy, one Space Opera, one anime, and one modern paranormal. (The last, called “Borrowed Time”, could also be overlaid on a fantasy or science fiction world; its central premise is that certain people can speed up or slow down time around them.)

Several supplements have come out, notably True20 Fantasy Paths which recreates most D&D classes using True20 mechanics. Some classes end up as a mixture of two roles (e.g. the Paladin is a Warrior/Adept), but it demonstrates how to bridge the worlds of D&D and True20.

Combat Changes

True20 uses the standard d20/OGL combat sequence: “flat-footed” and “surprised” conditions, initiative rolls, standard and movement actions, roll-to-hit, blah blah.

The main changes are the following:


True20 also looks good. It’s supposed to be a simpler d20 variant; combat in particular is supposed to go faster. My one reservation is that one role – the Adept – would get little or no use in my low-magic or no-magic worlds, leaving only two roles for players to choose from.

Other Variants

Here I’ll give a brief overview of other d20-based systems I’ve looked at.

Perfect 20

Perfect 20 is an even more stripped down version of d20 than True20, although it borrows many ideas. The part I have trouble with is the following, quoted from the first page:

I’ve never liked the idea of classes to begin with; this retains the class mechanic, with its linear advancement, without actually designing any classes. It’s deciding the rest of your character’s life at first level.

Live System

James Desborough’s Live System also removes classes, putting a number of mechanisms in their place:

Experience points can augment all the other statistics, including Hero Points.

There’s a lot I skimmed over, notably Magick and Psionics, but in general it doesn’t seem to depart too far from the SRD apart from classlessness and yet more magic/psi systems.

If I had to use something d20-ish, maybe I’d use this system. However, if I’m going to use a skill-based system I’d rather use FATE, some other FUDGE, BRP, or GURPS. (Someone on the RPGNow site described Live System as “GURPSified” d20 … a fair assessment, although even GURPS doesn’t have this sort of cruft.)

“Frank’s Ultra-Simple Game What Uses a d20”

While I won’t claim this idea is really d20, or even OGL, those who like a d20 die could use these “rules”:

  1. Players define characters solely through skill ranks. The GM will draw up a list of skills, including replacements for the various basic stats and saving throws. Players allocate a number of skill ranks, up to a set maximum bonus.

  2. When a conflict comes up, a player rolls a d20, adding in a “primary” skill plus 1/5 the bonus (rounded down) of any supporting skills, as arbitrated by the GM. If the total meets a fixed difficulty factor, or exceeds a non-player character’s roll, the player character wins the contest. If a PC ties an NPC’s roll, the “defensive” skill wins. E.g. if a PC’s Sneak roll ties the NPC’s Watch roll, the NPC wins, but if a NPC’s Attack ties a PC’s Dodge, the PC wins.

  3. There is no Rule #3.

Yes, this looks a lot like HeroQuest, FATE or PDQ. So?

(NOTE: This looks somewhat like the as-yet-unreleased “Bullseye 20” system used in Passages from Blue Devil Games. I will evaluate it next time.)

d20 Options

Many authors have spilled much real and digital ink proposing additions, replacements, and outright rennovations to standard d20 rules.

Alternate Classes

If I simply didn’t like the existing D&D classes, I could take a look at Green Ronin’s Master Class series, the Unlikely Heroes PDFs available at RPGNow, and any number of products. I’m sure I could cherry-pick some that fit my idea of magic, and added more skill-based classes to the mix.

Alternate Combat

If I didn’t like the complex combat system, I could try Narrative Combat by Shannon Kalvar. A horde of foes or a complex series of actions becomes an Encounter Template, which the players must defeat by exceeding one or more Threshholds of damage dealt, successful skill checks, spells cast, and other actions. The PCs’ actions themselves become “stances” which determine whether that character is dealing damage, defending other characters, performing some other relevant action, or taking a moment to rest and reflect. It’s interesting up until he tries to tie it back into d20 feats, spells, weapons, and skills.

Kenneth Hood has also written Grim & Gritty Hit Points and Combat Rules, which I haven’t read yet. From the Overview on the first page, it exchanges higher HP at low levels for much lower HP at high levels, divides Armor Class into “Defense Score” and “Armor Points” similar to Iron Heroes, judges critical hits based on the difference between the target number and the roll, and adds rules for realistic trauma. It might make a good fit for my low-magic, negotiate before attacking sort of games … but so would a lot of non-d20 rules.

Alternate Magic

While I haven’t covered magic, there are plenty of alternate magic systems out there, including Green Ronin’s Psychic’s Handbook and True Sorcery, Atomik Vortex’s Atomik Magick, and plenty of others on RPGNow and elsewhere. I’ve yet to find the perfect one, although Psychic’s Handbook comes close for a few campaign ideas.

Combat In Other Systems


GURPS also fits the D&D combat sequence closely, but with some decidedly different details.

GURPS combat takes place in one-second turns. Most characters have just enough time for one action: attack, defend, move, cast a quick spell or prepare a slow one, etc. (A few expensive advantages can grant more than one action per turn.)

Initiative proceeds in order of Basic Speed ((DX + HT)/4, keeping fractions), with DX and then a die roll settling any ties.

Attacking players roll against their weapon skill, adjusted by circumstances; defending characters can Parry with a weapon, Block with a shield, or Dodge if nothing else to avoid damage. If that fails, the attacker rolls damage based on the weapon; for low-tech weapons like swords or bows, the strength of the arm wielding a weapon makes as much of a difference as the weapon bonus.

Because of the shorter turns, there’s really only one type of action: anything you can do in a second. The short turns make combat simpler; for example, GURPS has no equivalent to Attacks of Opportunity; the rules presume you’re backing away slowly and not turning tail and running like a moron. Otherwise, anyone can attack you if you’re in range, and if you’re not armed they can usually keep you at bay.

GURPS has a plethora of rules for just about any situation, but most of the combat rules are optional, including using Tactical Combat (i.e. a map). The net effect – to me, at least – is a streamlined blow-by-blow combat system which covers tricky situations or more tactical options if I want them.


Since there’s no one definitive BRP (yet), there are multiple “combat rules”.

In Call of Cthulhu, attacks in a round occur in DEX order, although all firearm attacks with ready weapons are resolved before melee attacks or shots where the gunman first had to draw his weapon, or gets another shot after the first. In each case, the character rolls against the relevant combat skill; a defender can dodge any attack, or parry a hand-to-hand attack if the weapon can parry and he has not already parried another attack with that weapon. If the Dodge or Parry skill roll fails, the attacker then rolls for damage, subtracting the defender’s Armor Points (if any). Creatures usually have special attacks, and there are some brief rules about different types of weapons, but that’s the gist of CoC combat.

In Runequest 3e, each player makes a Statement of Intent at the start of a round. Players resolve attacks in order of “Strike Ranks”, calculated from the size and type of weapon, and size and speed of the wielder. There’s additional rules for Knockback and a few other conditions, but otherwise it’s similar to Call of Cthulhu.

The general pattern seems to fit D&D, but with a greater simplicity. Note that BRP and its offshoots, unlike d20, does not depend on a tactical map, nor does it have explicit “line of sight” or “area of control” rules that require a map.

Fudge FATE

FATE has three different options for conducting combats: Scene-based, Exchange-based, or Turn-based. All essentially compare two die rolls; the victor’s margin of success determines the loser’s penalty (Scratched, Clipped, Hurt, Injured, or Taken Out).

FATE rules are far lighter, and give the GM more discretion. Any tactical advantage or disadvantage reduces to a bonus or penalty to a die roll, and the GM can assess them on the fly.


HeroQuest combats are far more abstract than in d20 or most other games. Either the GM can settle them with a Simple Contest if it’s not important, or he can elect for an Extended Contest in which parties wager Advantage Points in a series of die rolls; when one party goes in debt, the amount he goes into debt determines the severity and consequences of his defeat. The rest is narration.

Additional rules cover the effects of multiple combatants, the use of magic, assistance from other characters, tactical advantages, etc, but it all boils down to bonuses and penalties to the die rolls.

Note that, as stated last time, the same rules cover duels, debates, long-term seduction attempts, and any other conflict situation. The elegance of using a single set of mechanics appeals to me, especially since I’d rather run a thrillingly narrated combat punctuated by die rolls than a set of die rolls punctuated by narration.


One of the draws of d20 is that it’s a system that “everyone” knows. However, since I’ve rejected the idea of a vanilla D&D game, I’m left with three options:

  1. Stitching together a new game from alternate rules and my own inventions, which are rules few people would know.

  2. Using a well-known commercial set of rules like Iron Heroes or True 20, which also depart from the Players Handbook and the rules “everybody” knows, and cost $40 hardcover or $20 PDF.

  3. Using less well known rules like Live System, which also cost about $10 in PDF form.

If I’m going to pour time into custom rules, I’d like to start with a simpler base like PDQ or FUDGE; jumping on the d20 bandwagon simply to invoke the name is so 2003. If I’m going to use someone else’s rules, I’d like to ensure that either a) the rules are simple enough to pick up in one session, or b) that it’s a ruleset a lot of people would know, which leaves out option #3.

However, picking a ruleset to attract the largest pool of players is a mug’s game. If I’m going to run a game, I should enjoy using the chosen ruleset, otherwise the game suffers and I have no fun. I would much prefer a small gaming group who enjoyed the game to a large gaming group miffed that they can’t play the cool Half-Elf Half-Kobold Dragonkin multiclassed Favored Soul/Darkblade they came up with.

So that leaves me with Iron Heroes or True 20, along with what I can extract from Passages, which I will consider on their own merits next time.