Steve Jackson Games GURPS – Generic Universal RolePlaying System

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6. Magic

6.1 How should clerical magic be handled?

GURPS Religion contains several different methods of handling clerical magic. In its simplest form, it works just like regular magic, except Power Investiture replaces Magery, sanctity level replaces mana level and holy items replace magic items. However, Religion presents a great deal more detail than that for those who want it!

GURPS Compendium I also contains a number of advantages and disadvantages appropriate to clerics, including Clerical Investment (p. CI22), Pious (p. CI29), Blessed (p. CI34), Clerical Magic (p. CI35), Divine Favor (p. CI36), Faith Healing (p. CI36), Power Investiture (p. CI42), True Faith (p. CI47) and Disciplines of Faith (p. CI89).

Source:Dr. Kromm

GURPS Magic includes guidelines for clerics on pp. 94-96. In summary:

For more detail, make up appropriate packages of mental disadvantages for each different priesthood. Using the Roman Catholic church (in medieval times) as an example:

    Order           Disadvantages
    Jesuits         Fanaticism
    Franciscans     Pacifism (total non-violence)
    Dominicans      Compulsive Behavior (arguing) or Laziness

All of them would probably have a Vow of chastity and Intolerance of non-Catholics (if basing things on a pseudo-medieval Church).

Sources: Bryan J. Maloney and Jim Frost

As the good doctor suggested, it is quite possible to create a cleric that do not depend on spells at all. I personaly prefer this method as it really gives an impression that the cleric's power comes entirely from his god. Good advantages, aside from the normal ones like Clerical Investment, are Patron (God, 6-) for the occasional miracular intervention, Blessed, Faith Healing, Divine Favor, True Faith, Reputation (God's servant), Claim to Hospitality and Ally Group (Followers). Good disadvantages include Fanaticism, Pacifism, Intolerance and Enemy.

Source: Stephane Theriault

Also, the magic system in GURPS Voodoo and GURPS Spirits works very well for priestly magic. The basic idea is that the caster is calling upon a willful, self-aware power to grant him or her the magical effect asked for. Extended rituals, mystical symbols, and sacrifices can increase the effectiveness, but usually aren't necessary. The spells can be much more far-reaching than standard GURPS magic, but they are more subtle, and usually take long enough to cast that they are not usable in combat except by extremely powerful casters.

Source: Kevin J. Chase

6.2 When does a spell go off?

For a standard one-second spell, the mage takes the concentrate maneuver one turn, and the spell goes off at the beginning of the mage's next turn. This is when the player announces the target, rolls the dice, etc.

6.3 What sorts of spells count as spells "on"?

Spells with instantaneous effects (e.g., Awaken, Deathtouch) never count as spells "on". Non-instantaneous spells fall into four basic categories. Spells that require fatigue to maintain (e.g., Charm, Light) are temporary spells. Spells that have ongoing effects that require no fatigue to maintain, but which have a limited effective duration (e.g., Bless, Continual Light, Curse), are lasting spells. Spells that have ongoing, permanent effects (e.g., Enslave, Great Geas, Zombie) are permanent spells. Finally, there are enchantments. Of these, only temporary spells count as spells "on".

For the record, Flesh to Stone, Major Healing and Resurrection are all "instantaneous". They produce a momentary pulse of magic that leaves behind a permanent non-magical effect (a statue, healed wound or living human). For a spell to be "lasting" or "permanent," the ongoing effect must be magical, not mundane.

6.4 Which spells are canceled by a no mana zone?

Temporary and lasting spells are simply dispelled by a no mana zone (NMZ). Permanent spells and enchantments are merely suspended, and resume their normal function once they leave the NMZ.

6.5 How many mages make a circle?

Magic implies, but does not explicitly state, that it is expected that Ceremonial Magic is performed by 2+ mages. In fact, this is the case.

6.6 Can you mix regular and aspected Magery?

Yes. You're simply more talented with some spells than others.

6.7 Can I leave holes in an area effect spell to avoid catching friends in it?

The second paragraph under Area Spells on p. M11 state that an area spell doesn't have to affect every hex within the spell's radius, but you still pay the full fatigue cost as if you had filled every hex. For instance, Create Fire could call into existence a normal n-hex radius circle of fire, a semi-circle of fire, or a wall, crescent, or bow-tie of fire, as long as they all fit completely within the n-hex radius paid for.

Source: Kevin J. Chase

6.8 Can I arrange the hexes an area spell would have filled in some other shape, like a wall?

The short answer is "no". A rules expansion in GURPS Grimoire was going to allow this, but it was cut from the original playtest draft. (The "Size of Area Affected" sidebar on p. G5 was put in for that reason and never cut.)

See the question on shaping area spells for the ways you can alter an area spell.

Source: Dr. Kromm

6.9 How exactly does the Force Dome spell work?

What kind of creature can walk through a Force Dome?

Supernatural creatures such as a demons can walk through a Force Dome (p. M78). The Force Dome keeps out "mundane" creatures.

"Awakened" beings, mages, creatures that don't depend on mana to exist, and creatures that aren't created or summoned magically are regarded as "mundane" as far as standard GURPS magic is concerned. This means that they cannot pass through a Force Dome.

Source: Dr. Kromm

What happens to something caught at the boundary of the Force Dome when it is cast?

Anything that is caught at the boundary of a Force Dome when it is cast is either dragged into the dome or forcefully expelled. Roll 1d: on 1-3, the object or being is expelled from the dome; on 4-6, it is caught inside.

Source: Dr. Kromm

Can a Force Dome enclose a no mana zone?

A Force Dome may enclose a region without mana as long as it meets two criteria: (1) No edge hex of the dome is a hex without mana. (2) The dome is tall enough that the enclosed no mana zone (which extends 12' above the ground) will not cross the dome. Note that a Force Dome must be at least 5 hexes in radius to be 12' or more high at its center.

Source: Dr. Kromm

What happens when two domes intersect?

They interpenetrate, creating three isolated compartments:

        ______  ______
       /      \/           /       /  \          /   1   /   2  \   3   

Source: Dr. Kromm

Are Force Domes spheres or hemispheres?

Force Domes are really spheres of magical energy, with the top hemisphere showing and the bottom hemisphere engulfing mass as a magical (not physical) "anchor". E.g., a 3-hex Force Dome radiates 2 hexes out from the center hex, and is 5 yards (15') in diameter. It must be cast on a patch of ground at least 15' across, and appears to be a "dome" 7.5' high in its center. The other hemisphere is under the ground, full of dirt, stone, or other solid junk. To uncover the whole sphere, cast Disintegrate, Earth-to-Air, Teleport Other or something similar on the mass in the sphere after you have cast Force Dome.

Source: Dr. Kromm

Is a Force Dome useless to flying characters?

Yes, a Force Dome is worthless in aerial encounters, unless you can cast a large enough dome on the ground that it engulfs you or low-flying foes.

Source: Dr. Kromm

Is it useless to a swimming character?

Yes, unless cast on the bottom of a body of water, in which case it makes an exceptional pressurized capsule!

Source: Dr. Kromm

Can a Force Dome be cast on the deck of a moving vehicle?

A Force Dome can be cast upon a large, moving platform (like a vehicle) and remain stationary with respect to it, as long as it is completely anchored on the platform; i.e., provided that the lower hemisphere of the dome can be completely contained within the vehicle. Note that in this case, the dome is "anchored" using a big chunk of vehicle, and any electrical cabling, fuel lines, et cetera that cross the boundary of the dome will not function!

Source: Dr. Kromm

Once the full sphere is uncovered, is it subject to gravity (a physical force)?

Yes. If the dome has any contents, gravity will pull them down, bringing the dome with them.

Source: Dr. Kromm

In the case above, would the occupants take falling damage when they sphere hit the ground?

No. The dome can absorb infinite physical force, so the people in the dome would hit the wall and the dome would absorb their kinetic energy, leaving them unharmed. In fact impact with a Force Dome is always harmless.

Source: Dr. Kromm

How much does a Force Dome weigh?

Nothing, except for the weight of people and dirt inside.

Source: Dr. Kromm

Can an Apportation spell move just the Force Dome itself?

No. Apportation requires a massive, physical subject; a Force Dome is a massless construct of mana, and it cannot be Apported. If you want to move it, use Displace Spell (p. G70).

Source: Dr. Kromm

Can a Force Dome absorb any force, even a nuke?

A Force Dome can absorb infinite amounts of energy - even the blast of a nuclear weapon. It works by converting the absorbed energy to mana and dumping it into the local mana field (perhaps recharging the mana that is used up by wizards).

Source: Dr. Kromm

As a clarification, the spell description on p. M78 says the energy is repelled. This is wrong. As Dr. Kromm described, the energy is absorbed, not repelled.

Source: Stephane Theriault

Will a magically created physical effect like a lightning bolt or a fireball go through a Force Dome?

Per p. M78, "the Force Dome will repel any physical force or missile spell."

Source: Dr. Kromm

Can I cast a Force Dome around somebody and then suffocate him by destroying all the air inside it?

No. Force Dome includes a Weather Dome effect, and the main effect of Weather Dome is that "inside the dome, the air remains fresh."

Source: Dr. Kromm

What does having a Weather Dome effect in a Force Dome really means?

The problem here is that the Weather Dome spell description is rather vague. However, if it can repel forceful jets of air (as the Windstorm spell) and volcanic ash, per the text, then it seems safe to assume that it can repel airborne dangers in general. Repelling the Windstorm spells means that it maintains constant air pressure, hence the ruling that a Force Dome always contains breathable oxygen-nitrogen at 1 atmosphere (for a human caster), no matter what.

Source: Dr. Kromm

What if the caster is not human?

The temperature within the dome is always right at the midpoint of the caster's "comfort zone," and the atmosphere is always whatever gas the caster normally breathes, at the pressure he usually breathes it.

Source: Dr. Kromm

With all of that, how can I use Force Domes offensively?

Force Dome is intended to be a defense for the caster and his companions, not a prison for the caster's enemies. The spell cannot be evaded or resisted; therefore, allowing mages to trap people in Force Domes to incinerate them, depressurize them, etc. would be abusive, and not in the spirit of the spell.

Source: Dr. Kromm

While Force Domes by themselves are pretty useful for capturing people, it is entirely possible to use them for traps in combination with spells not based on physical effects, like Sleep, Flesh to Stone, etc.

Source: Stephane Theriault

6.10 What exactly is a fireball?

According to Steve, an orange-sized bolt of magical force that hits like a bullet and which quickly vanishes in a blast of fire on impact, detonating any flammables it actually strikes.

Source: Dr. Kromm

What temperature is a Fireball?

About 300 degrees centigrade.

Source: Dr. Kromm

What kinds of wounds does a Fireball cause?

It is largely an impact weapon; a baseball-sized bolt of pure magical force. This is why it's damage is stopped by the DR of the location hit. It is hot, and it does vanish in a gout of flame when it hits the target, but that's more of a special effect than its primary mode of doing damage.

Source: Dr. Kromm

How does a Fireball interact with armor?

This "hard" bolt of magical force hits the armor just like a bullet, staff thrust or fist, doing damage on impact, and either denting it a little or punching a hole straight through. It then goes "Poof!" and vanishes in a cloud of fire. It will only heat up a breastplate as much as a baseball-sized globe of 300-degree air would; i.e. not much.

Source: Dr. Kromm

Does unsealed armor protect against an Explosive Fireball?

Yes. Here's how it works:

The Explosive Fireball does flame damage - treat as crushing damage that can set fires. It is not a true explosion, but damage decreases with distance in a manner similar to explosive concussion damage. The target may attempt to dive for cover (p. CII54) to get away from the center of the blast, but PD is ineffective. DR protects normally; assume torso DR unless the target is hit directly by an Explosive Fireball aimed at another body part.

Source: Dr. Kromm

6.11 How many spells can a mage cast in a turn?

In GURPS, "casting" = "rolling the dice for a spell". You may do that once per turn, normally - twice, if you cast a blocking spell. In other words, on any one turn, the effects of no more than one spell (other than a blocking spell) may commence. For example:

  Turn 1: Concentrate on spell A (1 turn).
  Turn 2: Cast spell A.
          Cast Blocking spell.

If you have a zero-time spell, the sequence of events would be:

  Turn 1: Cast spell B (no casting time).
          Concentrate on spell A (1 turn).
  Turn 2: Cast spell A.
          Cast Blocking spell.

It's a safe assumption that if a single mage causes two spell effects to appear in one turn, the rules have been broken, unless one spell is a blocking spell.

Source: Dr. Kromm

Unless you have the Compartmentalized Mind or Altered Time Rate advantage, of course.

Source: Stephane Theriault

6.12 The "Rule of 16" makes it too easy to resist spells!

[Moderater's Note: Since its inclusion in this FAQ list, the "Rule of 16" has been officially re-written. A brief description of the original problem, and the rule as it currently stands will be included here as long as the subject remains Frequently-Asked.]

The problem was this: when a character was resisting a paranormal attack (Charm, Telereceive, etc.) the "Rule of 16" on p. CII190 reduced the effective skill of that attack to 16 before the Quick Contest took place. A character with lots of relatively cheap Strong Will and Magic Resistance could easily have had a resistance higher than 16, putting the attacker at a disadvantage regardless of whether the attacker's skill was 25, 30, or more.

The new Rule of 16 now states:

If the subject is a living being, the caster's effective skill cannot exceed the higher of 16 or the subject's actual resistance.

Source: Official GURPS Errata

6.13 How does One-College-Only Magery affect spell prerequisites?

To learn a spell, a character must know all the prerequisites for that spell. Magery is often not a requirement to learn a spell, and some spells have no prerequisites at all - anyone can learn them. To cast a spell, the character must know the spell, and have Magery in that college or be in a High Mana Zone.

The rules for a mage with One-College-Only Magery (p. CI39) are no different. He can learn a spell outside that college, provided he meets all prerequisites for that spell. (If that spell requires Magery, he can not learn it, because his One-College-Only Magery does not apply outside the one college.) To cast that spell, he will need to find a High Mana Zone. Once learned, the spell may be used to fulfill prerequisites for other spells.

EXAMPLE: A mage with One-College-Only Magery in the Illusion college could learn and cast Illusion spells normally. If he wants to learn the Phantom spell (p. G57), he would need Magery 2 in the Illusion college, Perfect Illusion, Hinder, and Apportation. Assuming he had the first two requirements down, he could start by learning Haste (p. M69), and using it to fulfill the prerequisite to learn Hinder (p. M27). Neither of these spells require Magery of any sort to learn. (They each require Magery in the appropriate college to cast, however; he can learn them, but not cast them.) Apportation, however, requires Magery in the college of Movement. He does not have this, so he can neither learn nor cast it; he cannot fulfill the prerequisites of the Phantom spell, even though it is in his chosen college.

The only exceptions to this rule are the spells Lend ST and Recover ST (both p. M49). They may be learned and cast by characters with any Magery at all, even One-College Magery in a college other than Healing. All other prerequisites (namely, that the character learn Lend ST before Recover ST) still apply.

Sources: Dr. Kromm and Kevin J. Chase

6.14 When does a mage have to specify his spell's target?

When he rolls the dice. In fact, the only thing you have to declare when you first start to concentrate is what spell you're concentrating on. The exceptions are spells like Divination and Seeker, which are worded so as to imply that one must start out meditating on a specific target object or question.

In general, the following things can be left up until the instant the dice are rolled:

Source: Dr. Kromm

6.15 How was the cost of the Garou package in GURPS Werewolf calculated?

It's too long to include here, but the author, Bob Schroeck, has posted the details.

6.16 How fast can an illusion move? Can it Dodge?

An illusion, as with all movable area spells, has a Move of 5 unless specified otherwise. An phantasmal knight in combat would therefore have a Dodge of 5. Its illusionary armor, weapons, and shield (if any) would not add to this for any purpose.

Source: Dr. Kromm

If the caster wants, he can make his illusionary knight appear to Block or Parry instead of Dodge, but in actuality it's still making a Dodge, against a score of 5.

Source: Kevin J. Chase

6.17 Can you cast Lend Health on yourself as a temporary healing measure?

An emphatic "no".

Source: Dr. Kromm

6.18 Can you recover fatigue while maintaining a spell?

You can always recover fatigue while maintaining spells, even if those spells have a nonzero maintenance cost. E.g., if you're maintaining a spell that requires 2 energy every 10 minutes and you have Recover Strength-15 (lets you recover 1 ST per 5 minutes), you can effectively recover energy as fast as you use it.

Source: Dr. Kromm

6.19 Can you aim while building up a missile spell?

No. The rules for Missile spells specifically require a Concentrate maneuver to build up the spell. Aim is another maneuver, and not a "free action" that can be added to Concentrate.

Source: Dr. Kromm

6.20 How does high skill reduce a spell's casting time?

To figure the reduced casting time of a spell known at very high levels, halve the casting time and round up at each stage (i.e., at skill 21, 25, 30, etc.). Do not just raise 1/2 to some power and multiply, then round up. The exception to the rounding rule is when halving takes the casting time below 1; then you round down to 0. In other words:

Original   Time at Skill Level
    Time   21  25  30  35  40 . . .
    1       0   0   0   0   0 . . .
    2       1   0   0   0   0 . . .
    3       2   1   0   0   0 . . .
    4       2   1   0   0   0 . . .
    5       3   2   1   0   0 . . .
   10       5   3   2   1   0 . . .
   30      15   8   4   2   1 . . .
  300     150  75  38  19  10 . . .
    .       .   .   .   .   .
    .       .   .   .   .   .
    .       .   .   .   .   .

Source: Dr. Kromm

6.21 How do the penalties for repeated casting of healing spells add up?

Basically, you have a penalty of -3 x [# times you've rolled the dice for Major Healing for that person in 24 hours]. This means that you could try to cast it 3 times, fail all 3 attempts and roll at -9 on the fourth, having not yet healed a single point.

Source: Dr. Kromm

6.22 How does the Draw Power spell work exactly?

What is the limit on the amount of energy I can use with Draw Power?

There is no limit. However, if you draw more than your personal limit ((Magery^2 * HT) / 4 MW), you have to make a HT roll each second or suffer one fatigue for every MW (or fraction of) in excess, every second.

Source: Dr. Kromm

Be aware that Draw Power in a setting where huge powercells exist can dramatically change the scope of a campaign, with feats like interstellar Teleportation and Force Domes covering entire cities now possible. The situation is even more problematic when ceremonial casting is available and the 'Trade Energy for Skill' rule is used. When used correcly, those elements can be a great asset for a high powered game, but for new GMs and those who prefer a more realistic style of play, they should be restricted, if not banned entirely.

Source: Stephane Theriault

The Conduct Power and Draw Power must use an active power source. Is a powercell an active power source?

A power cell is not an active power source, but it is a legal target for Energy spells.

Source: Dr. Kromm

Can I create a link to a power conduit or powercell in advance?


Source: Dr. Kromm

If yes, do I have to pay one fatigue per minute?

Only if you are actually drawing power. The cost to actually draw power is 1 fatigue per minute, no matter how little power you draw that minute. Otherwise, you can maintain your link as long as you are conscious.

Source: Dr. Kromm

If I establish a connection with a power source, and then move away from that source, will there be a problem when I draw the power?

No, the link is instantaneous and works across any distance. This means when you start drawing power, it will be as if you were right next to the power source, even if you're one galaxy away.

Source: Dr. Kromm and Stephane Theriault

6.23 How precise is the Reveal Function spell?

The functions revealed by Reveal Function are the high-level ones the designer intended for the device, but only in terms of how the designer actually visualized the functions - the spell cannot interpret scientific or technological principles unknown to the caster. For example, a device that opens gates, as developed by an advanced race that views gates as a means commuting to work, might have its primary function revealed as "enables quick and easy transportation."

Source: Dr. Kromm

6.24 Is Stop Power really a /TL spell?

No. Stop Power stops the flow of energy independently on how it was created.

Source: Dr. Kromm

6.25 Can Mage-Only items enchanted with enough Power to be considered "always on" be used by non-mages?

If a "mages only" item would produce an ongoing effect on the user (e.g., Flight), and has Power enough to reduce both its cost to cast and its cost to maintain to 0, then it will generate its magical effect at all times. As such, it is irrelevant who uses it. On the other hand, a "mages only" item that actually empowers the user to cast a spell (e.g., Deathtouch) will only ever work for a mage even if energy cost is reduced to 0. When in doubt, ask yourself the following question: "Does the item effectively grant the user an advantage, or does it just let him cast spells?" If the former, then anyone can use it once cost is reduced to 0; if the latter, then it remains "mages only."

Source: Dr. Kromm

6.26 Can a mage use Counterspell or Dispel Magic to counter the effects of magic items?

Counterspell and Dispel Magic are fine for removing magical effects cast on someone by a caster who is empowered to cast spells via a magic item. They have no effect whatsoever on magical effects affecting the wearer of an always-on item. For instance, a Sickness arrow makes the target sick until the arrow is extracted, but a Sickness spell cast by a mage wielding a staff enchanted with Sickness can be Dispelled normally.

Source: Dr. Kromm

To get rid of an enchantment, use Suspend Enchantment or Remove Enchantment, both found on p. M38.

Source: Stephane Theriault

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