Limited Mana

by Steve Kenson

Art by andi jones

The standard GURPS magic system assumes that mana is an unlimited resource, for all intents and purposes. Mages cannot deplete the local mana level except through specific spells like Drain Mana (p. M54). Mages cast spells using their own Fatigue to represent the effort of channeling mana. As a mage's skill increases, he can draw more energy from the surrounding mana with less effort (reducing the Fatigue cost). As the mana level increases, a mage can cast spells with less effort.

This article follows the assumption that mana is a limited resource, one that mages can use up. When all the mana is gone, magic is no longer possible. This idea can be found in fictional sources like Larry Niven's The Magic Goes Away and Roger Zelazny's short story "Mana from Heaven."

Limited Mana is a mana type, much like Unlimited Mana, separate from mana level. On limited mana worlds, only mages can cast spells, but casting spells requires no Fatigue. Instead, the energy cost of the spell is paid in "Mana Points" that must come from somewhere, either the environment or a storage item known as a "mana battery." Once Mana is used up, it is gone, so it is quite possible for a mage to completely deplete the mana resources of an area. It is quite possible that the Limited Mana style of spellcasting (where the caster spends no Fatigue) is the cause of this depletion; rather than putting some of his own energy into the spell, the mage puts all the burden on the environment.

In a Limited Mana world, mages get normal reductions in energy cost for spells known at a sufficient skill level (they know how to do the same spell using less energy). However, the cost to cast or maintain a spell can never be reduced below 1 point. A mage with no mana resources cannot cast spells at all. Likewise, the Power enchantment does not exist. Magical items are never "self-powered," although they may have dedicated powerstones (see below).

Mana Resources

The amount of "free mana" available from the environment is up to the GM. A single hex may contain 1 point of mana, more points or none at all. Free mana may only be available in certain places or at certain times. For example, during thunderstorms, volcanic eruptions, meteor showers or similar events. Over time, mages come to know what areas have free mana and what events provide it, and flock there to take advantage of (and, perhaps, fight over) the mana resources available. A mage in a Limited Mana world can roll against (IQ + Magery) to sense the presence of any free mana in an area.

If an area provides free mana, mages will most likely try to "harvest" as much of it as they can, tying it up in mana batteries (below) or in permanent spells like enchantments. A campaign can have a "mana rush" (similar to a "gold rush") when a particularly rich source of mana is discovered and all the mages rush there to grab as much of it as possible.

Mana Batteries

Mana batteries are physical objects that store mana for a mage to use at a later time, much like a powerstone. In fact, powerstones are one type of mana battery. The types of mana batteries available in the game are up to the GM. The limiting factors are that they must be physical, non-living objects of some kind. Each mana battery has a "Strength" that defines how much mana it can hold.

To use a mana battery, the mage must be touching or holding it. Some mana batteries may have quirks that require a mage to do other things in order to use them (see Quirks, below). A mage can normally only draw mana from a single battery at a time. If the battery doesn't have enough mana for the spell the mage wants to cast, the mage will know it and may choose to cast a different spell. This makes a larger mana battery more valuable and useful than several smaller ones. The GM can allow mages to draw mana from multiple mana batteries at once, if desired. This makes smaller mana batteries more useful, and encourages a mage to carry several rather than putting all of his mana "eggs" in one basket.

Recharging a mana battery requires putting additional mana into it. Mana batteries do not recharge on their own in a Limited Mana environment, their owner must specifically draw free mana into the battery to recharge it. Nearly all mages in a Limited Mana world know the Powerstone spell to create and recharge mana batteries. Recharging a battery requires a casting of the Powerstone spell (at no cost in Mana or Fatigue). For every point the caster makes the skill roll by, he may put one point of Mana into the battery, up to the battery's maximum Strength. A failure means no mana from that source may be stored in the battery. A critical failure on a recharging roll means the battery picks up an additional quirk (see below).

In addition to batteries created by mages, some Limited Mana worlds may have naturally-occurring mana batteries, objects that accumulate mana in their structure and can be tapped by mages. Such things may include magic mushrooms from a faerie glen, body parts from enchanted creatures (if they exist), water from a certain spring, and so forth. Mages will seek to find and control such natural resources, possibly leading to the extinction of some highly magical species. Perhaps there were unicorns and dragons on Earth once, until ancient mages killed them all for their mana!

Certain objects may also become mana batteries due to years or reverence or use by humans in spiritual or religious rites, making ancient talismans and artifacts useful as mana batteries, leading mages to plunder tombs and take up careers as archeologists and museum curators (or simply wealthy art collectors).

Most naturally-occurring mana batteries cannot be recharged. Once their mana is used up, they become ordinary objects. Some man-made items that become mana batteries can be recharged like other batteries. The GM decides the Strength of these items. Very high Strength batteries are quite valuable, and likely to be fought over almost as much as the mana they contain!


Also like powerstones, mana batteries may have "quirks" regarding how they are used or recharged. An ordinary failure in casting the Powerstone spell to create a mana battery or increase ones Strength adds a quirk to the battery. Naturally-occurring batteries may have their own quirks at the Gamemaster's discretion. The fewer quirks a battery has, the more valuable it is.

Quirks can be almost anything, from the type of spells the battery can be used for (enchanted water might be good only for Water Spells, for example), to things the mage must do in order to use the mana (chant, sing, dance, recite bad poetry, etc.). Some batteries have quirks limiting them to certain users (only women, or redheads, or virgins, or natives of a particular region, etc.). Rechargeable batteries may also have quirks about how they recharge (only while submerged in bat's blood, only using mana from active volcanoes, etc.).

Limited Mana

Limited Mana Mages

Mages in a Limited Mana world tend to be even more reclusive and competitive than mages in normal or even low mana worlds. The mage population may be quite small, depending on how scarce the mana resources are, and mages may deliberately keep their numbers low to share the remaining resources among themselves. If mages are especially rare, the Gamemaster may wish to charge an Unusual Background cost to possess Magical Aptitude.

Limited Mana mages always learn the Powerstone spell as soon as possible, allowing them to create mana batteries and "store up" mana for when they need it. They often have numerous caches of batteries concealed in various places in case of emergency. A mage's power depends greatly on the size of his personal mana "hoard."

In general, Limited Mana mages are more "miserly" with their magic, casting spells less frequently and casting smaller spells. Very powerful spells and enchantments are virtually non-existent, except for occasions when a group of mages can manage to cooperate together and agree to spend their precious mana on such a large spell. This makes Limited Mana very useful for "low-magic" campaigns as well as "secret magic" campaigns, where mages conceal themselves and their abilities from the general populace.

Mages spend a great deal of time simply maintaining their mana-stores. If free mana is rare in the world, many mages are constantly on the move, searching out sources of free mana to store and recharge their mana batteries. The Seek Magic spell (p. G60) allows a mage to locate the nearest source of free mana. Mages also learn what circumstances tend to create free mana and keep track of them. If free mana is a more regular occurrence, mages plan to take advantage of the occasions when it is available to recharge their batteries. Spellcasting may be more common right before "payday," as mages feel freer to spend energy, and rarer during "mana droughts" when free mana is less available.

There may be rituals and protocols for mages to follow regarding the gathering of free mana, such as the first mage present "staking a claim" or agreeing to divide the mana evenly or even ritual contests and magical duels to decide who gets the most mana. Alternately, mana gathering may be a free-for-all, the strongest and cleverest mages get the lion's share of the mana while everyone else gets whatever scraps they can scavenge.

Other Energy Sources

The Limited Mana option uses the same base assumption as the GURPS magic system: that mana is a natural resource unconnected to any other natural resource or energy. However, that does not have to be the case; mana could be derived from certain other natural or artificial sources, requiring mages to tap into those sources to get their mana. Two options are presented below.


In this case, living beings are the source of mana. In a normal mana campaign this has little effect except that the mana level of an area may be affected by how much life is there. Overgrown jungles or crowded cities may be High Mana while lifeless deserts are Low or even No Mana. Most of the world is Normal Mana.

In a Limited Mana world, mana is only available by draining the life force of living beings. In effect, a mage must kill (or at least deplete) a living being in order to use magic. This functions much like the Limited Mana described above, except the only mana batteries are living creatures.

A mage in this setting may drain the HT of a living being by touch to power his magic. Intelligent beings get a Will roll to resist this, roll a Quick Contest of the caster's Will and the subject's. The caster drains as many points of HT as he wins the contest by. Living creatures have a number of Mana Points equal to their HT. The mage must use this mana immediately. Any not used by the next turn dissipates into the environment. Alternately, mages may be able to store the mana in non-living batteries. When drained to HT 0, a creature dies and becomes a withered shell, its vital life force sucked away. A mage can use himself as a source of HT in this case. Ethical mages limit themselves to this method and taking HT from willing donors (but not enough to kill them).

This effect is not limited to just animals; plants may be used as well. Assume a hex of plants like grasses and shrubs has 3 HT, larger plants like trees have correspondingly greater HT. A mage may drain energy from plants in a radius equal to his Magery in hexes. So a mage with Magery 2 could drain HT from all the plants of the hex he was in and all plants within 2 hexes of that hex. Plants drained of all their HT wither and turn brown. A world where necromana is the only source of magical energy may become a barren desert as mages slowly suck the life from the world to power their spells.

Needless to say, mages have a poor reputation in a necromana world. Even "good" mages have a Reputation of -2, while mages known to casually drain life force to power their spells may have a Reputation of -3 or worse. An area where a mage lives will eventually become drained of life unless the mage is quite careful in the use of his powers. Evil mages will have numerous slaves and "pets" for use as sacrifices when needed. Regions they control will tend to become barren and inhospitable.

Energy Conversion

In this type of campaign, mana does not exist naturally, but is created by mages from other forms of energy like electromagnetic and kinetic energy using the Draw Power spell (p. G101). The mana created can be channeled into another spell or stored in a mana battery for later use.

In a low-tech Energy Conversion world, mages tend to flock towards natural energy sources like waterfalls, hot springs, volcanoes, lightning storms and similar locales, giving them a regular source to draw power from. (See More Power!, for more on this idea.) In a high-tech or ultra-tech campaign, mages will use modern conveniences like energy cells and power plants to power their magic, giving them a lot of energy to work with. A circle of mages drawing power from a fusion plant can accomplish tremendous spells at virtually no energy cost to themselves. Gamemasters take note! Of course, a mage with no energy source to draw from has no power whatsoever.

Article publication date: October 22, 1999

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