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I was never really satified with the AD&D magic system. It was not all that flexable, and attempts to alter it only seemed to make things worse (spell point systems didn't help the low level wizards and only served to boost the powers of the already powerful mid to high level wizards even higher). Magic item creation was another problem as there were no real guidelines which made determining the value of new magic items at best a guessing game.
Searching around for an alternative I encountered GURPS Fantasy 1st edition and found that with minor modifications this magic system could be used in AD&D. I have updated the modification sheet I created back in 1986 for GURPS 4e Magic and GURPS 4e Fantasy which can be used either for using the GURPS magic systems in D&D or as a convertion guide.
GURPS has several magic systems but for the most part they all are variations of the core system in GURPS 4e Magic making it the required book GURPS 4e Fantasy (F) is also strongly recommened for rules, concepts, and ideas. If you want to do a complete conversion you will also need the Basic Set (B) but that is beyond the scope of this page. Page numbers are preceded by the first letter of the book (’M‘ for Magic, ’F‘ for Fantasy, and ’B‘ for Basic just for completeness).
GURPS 4th edition has streamlined the mechanics of magic making tailoring the core GURPS magic system to your particular campaign far easier than it was in GURPS 3e. As a result 3e books like GURPS Religion and GURPS Spirits are more useful for the ideas regarding Clerics in them than for any mechanics they have.
To keep things easy to understand I will use GURPS terms to denote several different methods of magic:
A wizard is any user of magic reguardless of any
other advanges or skills. (B234, M5)
A mage is any being who possesses the Magery advantage
regardless of their ability to use magic. (B234, M5)
A magician (Revising the GURPS Spirits definition for 4e)
is any being who uses Ritual Magic (B242, F158, M200)
Invested is a term of my own which refers any being who
has the Blessed and/or Power Investiture advantages.
In GURPS all spells are IQ based skills with certain advantages providing bonues (or negating penalities) to learning them; by contrast in D&D the attribute that determines spells bonus is set by what class the character is. GURPS has two main ways of handling magic: as powers (which requires the Basic Set and is beyond the intent of this sheet), or as spells. In the spell system there several different mechanics each with its own strengths and weakness (F155-168). For the sake of simplicity treat magical advantages (like Blessed, any form of Magery, and Power Investiture) as Feats while treating everything thing else (including Ritual Magic and Thaumatology) as skills.
Fantasy’s Magical Arts chapter (F146-F172) is invaluable for sorting through the majority of options available. The many types of Magery available (F129) may seem a little daunting but they are are some familiar options here; Restructurable Magery can easily produce something similar to the cast and forget (in this case cast and use up Fatigue) system used by D&D.
As for actually becoming GURPS wizard it is easiest to assume that Magery 0 and beyond can be learned and the powers that can grant Blessed or Power Investiture are not too picky initially. The advantages of Magery and Blessed/Power Investiture fit very well with the idea that arcane and divine magic are fundementally different and the varients of Magery will help keep classes like the Sorceror and Bard distinct from the other Magery based wizards available.
Since in D&D the amount of the attribute determines the level of spells I use the bonus to reflect the level of Magery or Power Investiture the character can start out with as shown in this chart:
GURPS IQ = 10 + INT ability modifier
Modifier 0 = Magery 0; Blessed advantage*
Modifier +1 = Magery/Power Investiture 1
For each additional +1 = +1 to Magery/Power Investiture
However the bonues from an advantage are added in last for base skill level. So a INT 12-13 D&D3.5 Sorcerer would get everything as if he had a GURPS IQ of 11 (10 +1 ability modifier) and then add in a +1 for Magery (Ritual) 1 while a Paladin with INT 12-13 and WIS 14-15 would add in a +2 for Power Investiture 2. The reason for this is if there are any defaults (such as with Ritual Magic) the advantage is added in after the default values are calculated.
* The Blessed advantage actually covers any advantage granted to the character by a greater power. It can range from being able to cast a Divination spell to any particular advantage (including Magery and Power Investiture). Its main downside is that a Blessed character must behave in accordance with the vaules of this higher power or the ability is lost (In GURPS terms this is a Pact limitation and is built into Power Investiture).
Spells in GURPS are either hard or very hard skills (Ritual Magic has the colleges themselves as very hard skills and the spells within each college as hard techniques). In D&D treat these as Class skills starting at IQ-2 for hard and IQ-3 for very hard (techniques go from the default). When figuring out skill levels for Ritual Magic remember that advantages are added after the skill level and any related defaults are calculated.
Because spells in GURPS are skills GURPS wizards can easily have dozens of spells even at low point totals. The flip side of this is as skills each spell has to be improved individially. For this reason give D&D spellcasters (level+1)*attribute points in addition to what they normally get to buy spells with. That may sound like a lot but remember spell improvement is not automatic with GURPS spells; those extra skill points are needed to not only improve existing spells but to obtain new ones.
Fatigue is what powers spells and it is figured from HT (CON in D&D). Skill level not only determines the amount of ritual needed for the spell but also when high enough lowers casting time (for most spells) and energy costs. At skill 15 and every 5 levels afterward energy cost is reduced by 1 point. So a spell known at Skill 20 costs 2 energy points less than the same spell known at 14.
Since D&D hit points represent accual physical damage, skill, luck, and battle sence the effects of injury on spell casters as outlined in GURPS Magic needs to be modified. The easiest modification is to divide the total hit point by 10 and round down using the result as the ratio of injury penalities. For example say a D&D wizard has 25 HP. This means that for every 2 points of damage he receives he is at -1 to skill. Note in GURPS is possible to use HP to power spells; the problem is this counts as an injury lowering effective skill making the whole process counterproductive.
One of the biggest problems when different kind of spellcasters share the same spell list is that they can have this annoying habit of blending into one another rather than being distinct. GURPS allows GMs to address this problem by providing two variants to the main magic system: Clerical and Ritual Magic.
Under Clerical Magic Magery is replaced by Power Investiture and Mana level is replaced by Sanctity and clerics do not worry about prerequisites as their spells are granted by their deity. Ritual Magic is what magicians use and is denoted by Magery (Ritual). Instead of learning spells directly magicians cast them based on one skill (Ritual Magic or Thaumatology) they know with colleges defaulting from this skill and the individial spells defaulting from the college (B242, F158, M200)
The differences are not just in the names of the advantages but the underlining mechanics as well. While a mana level and type works the same for all mages the same is not true of sanctity for the invested; what is high sanctity to one deity may be low or even no sanctity to another even if the deities in question share the same sphere of influence.
Power Investiture also allows GMs a method of actually using ideas suggested in several Dragon #92 articles and addressed again in Dragon #101. The basic premice of the articles was that the power a deity has in a particular area (represented in GURPS by the sanctity level) is proportional to the amount of belief there is for the deity. Since belief is the exchange of power for deities one devout worshiper is ‘worth more’ then a 1,000 followers but conversely that one devout worshiper is more ‘vulnerable’ than 1,000 followers. In this context Power Investiture is not a “reward” to a cleric but rather an “investment” by the deity in the promotion of their worship (and therefore an increace in the deity’s power in a partucular area). As the Cleric shows/provides more worshipers, intensifies their belief, and promotes correct behavior the area’s sanctity level increases which in turn encourages the deity to improve the cleric’s Power Investiture. Conversely the cleric that misbehaves too much or lets too many of his deity’s worshipers be converted or killed sees the area’s sanctity drop which in turn results in the deity cutting back on the investment of Power Investiture power. If either sanctity or Power Investiture drops to zero then the cleric will unable to personally cast spells until he corrects the problem.
Since Power Investiture is an investment by a deity it means that they can use non-clerics (like Rangers and Paladins) to promote and increase their power base. Also some deities may become more demanding as they provide their clerics with greater power; for example behavior perfectly acceptable for a Power Investiture 1 Cleric of a codal deity maybe distained at level 2, frowned at by level 3, and completely forbidden at level 4.
Note: A special distiction must be made between Clerical Investment and Power Investiture. Clerical Investment is the Cleric’s social position and has nothing to do with Power Investiture. In fact it is the personality of the empowering deity rather than than the religion the cleric belongs to that will shape what is considered proper behavior by clerics. This really gets interesting is if the religion says one thing but the deity has other ideas.
Normally when people say magic they think spellcaster but that is not all there is. First there are magic items and no not all of them come from a wizard’s lab in the form of enchanted items. Natural, Alchemic, Fetishes, and Holy Relics are all items that may not have a wizard behind their creation. (F22-F28)
In addition to to non-enchantment magical items there is the type of magic available: Low, Formulaic, and High (F147-F152). D&D worlds tend to focues on High magic to the point Low and Formulaic Magic are almost invisable (the later mainly shows up in the creation of magic items though). This is where GURPS 4e Fantasy and Magic are head and shoulders over anything D&D has to offer as they provide a wealth of information; enough in fact that with a little work you can emulate about any magic system you want.
Take the Slayers anime series for example. It is clear from what Lina says in the first series that spellcasters are magicians in this setting. This gives you Magery (Ritual) as the main feat. Also Lina tells us that spells draw their powers from three sources: the Mazoku (demon/monster race), general spirits, and the ‘gods’ and a little internet searching reveals these are Kuro-Majutsu (Black Magic), Seirei-Majutsu (Shamanism/Spirit Magic) and Shiro-majutsu (White Magic) paths. To emulate the the varing power levels adding a reaction roll for the being who is being invoked makes the most sense machanicwise (so two rolls minimum are usially required for most spells) with something akin to the Demonic Contract (M157) but without the taint problem for better reactions and even using Lend Fatigue to further boost the casters spell.
For example the Mazoku Dark Lords in the Slayers universe seem to be very free with their fatigue as long as a spell is either cast in anger (+1 to +5) or to cause destruction (+1 to +5 the more destruction the higher the bonus). So the more mayhem and havoc the caster wants to create the better the reaction will be which in turn increases the energy available to the spell. This is why Lina's Dragon Slave is so powerful especially if she is mad when she casts the thing resulting in Lina becoming known as the “Walking Force of Destruction”, “Enemy of All Who Live”, and “Dragon Spooker”.
So for Slayers the reaction table could look something like this:
Poor: Caster has to use their own HP (Darklord) or FP
(Kami) to power spell. However if the caster survives they get a +1
reaction bonus for each additional time they cast the new spell up
to a maximum of +5.
Neutral: treat the caster as if they are in a very high
mana area.
Good: as Neutral but treat fatigue as per demon contract
with no obvious down side.
Very Good: As Good with called on being matching FP by
Wizard with Share Energy.
Excellent: Entire energy cost of spell provided by Share
Energy.
The important thing is that the level of detail and power level is set by the GM as they see the setting rather than the mechanics driving the game world. You can even have mana and Sanctity being at odds with each other as they are in Roma Arcana (F195-F232) setting rather existng side by side as they do in many D&D worlds.
In GURPS Fatigue whose based value is derived from Health (CON) is the exchange of spell casting magic. The more fatigue is put into a spell the more ‘powerful’ it is; however if Fatigue reaches 0 the character is at risk at collapsing unconscious (at -FP this is a given). Problem is if a combat lasts more than 10 turns a character normally spends at least (1 + encumberance level) points of Fatigue. Normally Fatigue is recovered 1 pt every 10 minutes of rest though there is a spell (Recover Energy) that speeds this up as far as spells are concerned. Note rest means sitting still or sleeping not walking around. Here we have a simple reason why GURPS wizards as a general rule do not go directly into battle; it would use fatigue which could be used to power a spell instead.
However is must be noted that in GURPS wizard means any spellcaster - reguardless of the spells being used coming from being Blessed, Magery or Power Investiture. This would put a major crimp on the classes that normally cast spells and wear heavy armor like the Cleric and Palidin if not for an advantages that deal with physical (but not magical) fatigue costs: Fit and Very Fit. In a way Fit and Very Fit are like the Armor Proficiency feats but instead of being able to move properly in the armor these advantages better model what armor training really was - getting use to the weight of armor. Fit replaces light and medium Armor Proficiency feats and doubles recovery rate, while Very Fit replaces the Heavy Armor Proficiency feat and adds halving of physcial fatigue costs to Fit. These advantages also provide other bonuses but they do not effect the wizards so we will simply ignore them. Another option is to have the armor enchanted with the Lighten (M67) spell but this is costly in terms of time and energy if you go for the 50% weight option. The Lighten Burden (M143) spell can be used as another alternative but it makes all other spells will be cast at -1 and requires Recover Energy and a high skill level to make maintaining it practical. Of course this may be provided by the deity as a Blessing in addition to Power Investiture as insentive to continute to promote worship.
The most important things to pay attention to in preventing abuse is fatigue [energy] costs, range (a hex is 1 yd), prerequites, and spell type limitations (like most non seek information spells can be cast only once per day). If a spell is being abused chances are that it is being played incorrectly. There is a quick reference spell sheet (M222-M237) which should always be at the GM’s fingertips to allow quick consulting if there is a problem.
It is important to note that GURPS not only has critical success and failure built into the system but they are on a sliding scale; in other words effective skill determines what die rolls are critial success and failures. The linear d20 has a real problem with this compared to the 3d6; if we ignore the sliding scale and use the old 1 and 20 rule we get this table:
| d20 | 20 | 19 | 19 | 18 | 16 | 14 | 11 | 10 | 7 | 5 | 3 | 2 | 2 | 1 |
| .019 | .046 | .093 | .162 | .259 | .375 | .500 | .625 | .741 | .838 | .907 | .954 | .981 | .995 | |
| 3d6 | 3-4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17-18 |
However GURPS does use a sliding scale. If effective skill is high enough 5 and even 6 become critical successes while if effective skill is low enough 16, 15, and even 14 become critical failures. Also resisting spells are handled by what is known as a ‘Quick contest of skill’ where the amount the skill roll succeeds by is as important as making the roll itself. However if the attacking spell critically succeeds no defence roll can be made!
For example a wizard with effective Crystal Ball 20 is trying to see into a Scryguard 21 area. He rolls a 9 (succeeding by 11) and the Scryguard rolls an 11 (succeeding by 10); the wizard sees into the Scryguarded area and the Scyrguard spell drops to 20. However if the wizard above had rolled 3 to 6 he would have seen into the Scryguard area and it would have dropped to 20 automatically!
As the chart above shows a linear system like d20 has problems with such a sliding scale especially when something like critical success and failures are built into it. On the d20 every number has the exact same chance (5%) to come up but the 3d6 clusters the rolls around the 8-12 area making it harder for an effective skill 7-14 wizard to automaticaly blast through a high skilled spell (1.9% for a 3 or 4 to come up) while at the same time giving him less of a change of the spell going really wrong (1.9% for 17 or 18 to come up) than would be possible on the d20.
For people and monsters add only the relevent ability modifier to 10 (HT uses Fortitude, IQ/Per use Will, and DX uses Reflex) for saves.
Magic Resistance is the GURPS equivalent of Spell Resistance with several important differences. For regular GURPS spells it subtracts from the effective skill of the caster which can increase the chance of a backfire. In addition it provides bonues to resisted spells (double for area spells). GURPS MR comes in two forms: regular (which cannot coexist with Magery) and improved (which can coexist with Magery) but neither form can be turned off so MR will interfer with all external spells helpful as well as harmful. Also if a non-regular spell is not resisted MR provides no benefits.
So a MR 5 being will incure a -5 skill penality to any regular spell and if it can be resisted like Beserker they get a +5 to their resistance roll, but while a caster gets no penality to an area spell like Terror the MR 5 being gets a +10 to resist it. A missle spell like Curse Missle incurs no penality for the spell caster and is resisted at only +5.
If you prefer only one 3d6 die roll for spells than assume a DC 16 with a modifier based on 16-the actual value. For Scryguard 21 this would be DC 16 modifier -5 (16-21). Note use this only to determine success or failure not effective skill level! This fits very well into the Rule of 16 which is designed to prevent high still level wizards from overwelming resistance rolls.
In GURPS there is an advantage and skill called Innate Attack. For our purposes the skill is our main concern as it is what is used with abilities or spells that are either beam, breath, gaze, or projectile. Note that for Innate Attack spells the wizard must make two rolls: one to see if the spell was cast and the other to hit the target. Enforce the default penalities and spell specific modifiers outlined in GURPS Magic because unlike their D&D equivalents these spells do not have a save for half damage option and magic resistance behaves differently.
The easiest way to up the power level is let wizards get lots of fatigue points or up the mana/sanctity level to very high. The down side to these methods is that letting wizard have buckets of fatigue even if it is Spells Only results in wizards casting insanely huge low cost area spells. Very high mana level makes magic more common decreaing the status of a wizard (though not mages).
Another alternative is to combine the Ritual Magic concepts from 3rd and 4th edition and allow wizards to draw power from the spirits they call on rather than the mana around them. This could be handled by a reaction roll on how the spirit viewed the spell being cast as per the Slayers anime example above; on a favable reaction roll Lend Energy is cast by the spirit. The problem here is if the spirits have loads of fatigue they eagerly lend out your wizards suddenly become Lina Inverse Jr and can lay waste to large hunks of the countryside.
S. John Ross's Unlimited Mana is another option but it has some problems as well. Its main problem is nothing for the Invested and can result in really bad things happening if the mages get careless with how much magic they throw around and start making Calamity rolls on a regular basis. Also certain Tech spells need modification to work under this alternative form of mana.
On a more modest level there is Aspected Mana (F43-44) which will enchance some spells while hindering others. For example, the elemental planes of Air, Earth, Fire, and Water would have the most exteme forms of Aspected Mana, being very high mana for their respective element while no mana for its opposite.
As outlined in GURPS Fantasy (F22-25) there are three broad catagories for magic items via GURPS: Natural, Alchemic, and Enchantment.
As the term suggests these are things that pick up an enchantment naturally. Plants and certain minerals can have magical properties and it may the task of the adventures to find out what those properties are. Such natural magic items usially have a handfull of abilities. For instance a four leaf clover was believed to break faerie enchantments and garlic was thought in some areas to ward off vampires. A weapon passed down a line of very skilled fighters may bestow their skill onto a future owner and so on.
This replaces the D&D skill of the same name and allows the creation of ‘elixirs’ (potions, powders, pastilles, and unguents). Note that in GURPS alchemy skill is totally seperate from being a wizard so anyone can learn and use alchemy. However wizard alchemists can have access to spells like Mature (M78) and Distill (M79) which allow them to spell up elixir production. While written for 3e Steffan O’Sullivan’s “ Historical Alchemical Elixirs for GURPS Magic” and “ Talismans” articles provide good examples of what can be done with elixirs and alchemic magical items.
This is how the majority of D&D magic items are made and this is where the bell curve of the 3d6 becomes important. Since each enchantment spell’s chance of Critical success (3-5, 6 if effective skill is 16+), normal success, quirking (on a roll of 16 if using Quick and dirty enchantment), or destoryed the item (17 and 18 are always critical failures regardless of skill level) is seperate, you can figure the cumalative chance of all three outcomes buy multiplying the chances together and using the skill chart to do everything with one die roll (and no Diviation spells will not improve Enchantment success).
| 3d6 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 |
| .046 | .093 | .162 | .259 | .375 | .500 | .625 | .741 | .838 | .907 | .954 | .981 |
For example you have a magic item with 3 spells on it all skill 15. The chance the item was not destroyed in the enchanment process is .981^3 or 94.4% but the chance all the spells succeeded is .954^3 or 86.8%. Under Q&D enchanment the 86.8% represents the chance that none of the spells were corrupted. So by the chart above a 15 means the item survived the enchantment process but a 13 or lower means all the spells worked the first time they were cast or it has no quirks.
To figure the odds that a magic item had at least one critical success during enchantment use the chance that a critical success was not rolled and subtact it from 1. For example assuming skill 15 take a magic item with 5 spells on it. The chance that at least one of these spells critial succeeded is 1-(1-.046)^5 or 21.0%. At skill 16 the chance increaces to 38.6% (1-(1-.093)^5). By the chart above a 3-7 tells us that for skill 15 at least one spell critial succeeded while 16 in all five spells makes 3-9 the determining roll.
Note that unlike D&D magic items GURPS magic items do not have to be mastercraft (fine or very fine) quality. However if the item that has been enchanted is broken the enchantment ends so it makes sense at least in the case of armor and weapons to use the best quality one can get ahold of. Also whoeenchantment covers holy relics these are enchanted by a higher power not the cleric. Such items have their own set of rules and guidelines for use which is up to the GM to flesh out.
A critial factor to remember is that most GURPS magic items cost their users fatigue. Mages have only two options to reduce this fatigue cost for enchantment: use the Power spell or have a Powerstone built into the item (dedicated or exclusive). As a matter of practicality in time and energy dedicated Powerstones will be the most common option used by mages.
Powerstones are nothing more than magic batteries. You may want to add Powerstones to your treasure awards to reduce spell costs but too many of them will make wizards very powerful. Powerstones built into magic items are more efficient than ‘loose’ Powerstones: dedicated Powerstones act if they are double their FP and exclusive Powerstones act as if they are tripple their FP. The main difference between dedicated and exclusive Powerstones is that magic item with exclusive Powerstones can only get their power from the Powerstone - once it is exhausted the item is useless until the exclusive Powerstone recharges. This makes exclusive Powerstone an effective way to simulate D&D magic items with ‘charges’ in GURPS.
Note that in addition to a FP level Powerstones have a Power level as well. By standard rules a Powerstone must be Power 20+ to charge or be used in a low mana area. If this is a hassle then just ignore it. Another possiblity is that Charge Powerstone has been used in the enchantment which effectively halves recharging time for each usage. Note that no Powerstone will recharge if an larger powerstone is within 6 feet of it.
Note that not all items that are magical in D&D are magical in GURPS. For example the librams, manuals, and tomes that raise a reader one level in D&D are simply well written instrution books that eliminate the need for a teacher in GURPS. As such they have three important limitations: they can only teach skills for which the player already has the nessasary prerequisites and/or defaults (they assume some basic knowledge of the subject), they are helpful only if the skill level of the writer is higher than the reader, and the 200 hours = 1 character point rule still applies.
In D&D the bonus of magical armor can be represented in GURPS terms by Deflect, Fortify, or some combination. There are two important points to keep in mind. First unlike in D&D GURPS magical armor weighs the same as non-magical armor unless it has been enchanted with Lighten and this spell at best only halves the weight. Second, if a piece of armor accures enough damage (natural DR*5) without being repaired magically (Repair spell) the armor looses its enchantments.
You may have noticed that the GURPS spells Accuracy (to hit, M65) and Puissance (to damage, M65) only go up to +3. Weapons above +3 are possible but they require more than simply Accuracy and Puissance.
Cutting and impaling weapons like knives, swords, axes, and polearms can be of better quality but this only increaces damage not to hit; fine quality is +1 and very fine quality is +2. The higher quality weapons are expensive averaging seven times normal cost for just a fine weapon. Penetrating Weapon (M63) is another alternative for damage but it is only effective against armored opponents. Neither option works for crushing weapons.
Lend Skill (M47) can add as much as +4 to skill level but it cannot raise skill level above that of the caster. This means that not only must the mage be skilled in enchantment but in the skill itself making high level items a rarity.
The addition of the Bless spell (M129) can add as much as +3 on top of other magics. The Bless spell has an additional “mortal danger” advantage which activates to help avert or reduce one major serious danger to the owner of the item. The major disadvantage is that the triggering of this “mortal danger” feature of the Bless spell results in the spell ending. Note that Bless items cannot be stacked; only one bless overall can be active at one time.
Looking over GURPS Magic it should be clear that the more powerful a magic item is the more mage days it takes to make. Also remember the more spells an item has on it the rarer and more expensive it will be. Simiarlly D&D magic items that seem to best represented by a GURPS spell that normally cannot be enchanted on an item can be ruled as a Critical Success, Q&D regular failure with another spell depending on whether the spell is benificial or harmfull, Symbol Magic (M205-209), or something that is a product of the item's history. Regardless of how the item is created it will be rarer than a “standard” magic item which in turn will increase its value.
Note that since a magic item looses its magic when broken the items the party will find will usially be of high quality or very well taken care of. So that Sword +1 is more likely to a very fine blade (already +1 to damage) enchanted with Accuracy then a cheap blade enchanted with Accuracy and Puissance (the later was more likely to break and would have taken twice as long to make)