Abracadabra.
The following is heavily related to GURPS mechanics. The point being made, however, is not exclusive to GURPS. This is intended to be the postulation for a manner by which to simulate the casting, knowing, and balancing of magic within the confines of a roleplaying game system.
GURPS is very good at modelling things. I am currently designing a conversion of the Pathfinder Jade Regent Adventure Path to the GURPS system because I am enjoying the challenge of putting the blocks together in order to simulate the feel that Paizo is capable of delivering with its adventure paths, but in another system. I am actually finding it not very much of a challenge at all; it’s relatively easy and enjoyable to do when a system does not stifle you in this regard.
One of the things I found a need to model in the GURPS system is a magic system that differs from the standard, more fatigue-based system that comes bundled with it. While designing the document that I will be providing to my players in order to ease the transition to GURPS from a d20 system, and in order to explain the rules of the campaign, I found myself dabbling in a number of supplements and external resources to try and construct something that feels like a magic system employed in Golarion. I may have taken a little liberty and put my own twist on it, however.
This is a summarized excerpt from the Player’s Guide to my forthcoming GURPS campaign intended to be adapted on the Pathfinder Jade Regent Adventure Path. Because the guide is a mostly dreary read filled with meticulous definitions, I will highlight a few ofthe more important thoughts here.
Casting
Instead of drawing from Fatigue Points (FP), which is the typical way of doing things in GURPS for magic, I am using Threshold-Limited Magic, an alternate ruleset proposed in GURPS Thaumatology. All casters in this system possess a power tally. All spells, when cast, add their appropriate energy cost to this tally. If this tally exceeds a designated threshold, the player must roll on a Calamity Table.
The proposed threshold for high fantasy here is 25. Every hour the spell caster is capable of resting, their tally is reduced by (Magery or Power Investiture)/2 rounded down with a minimum of 1 and unable to be brought below zero. In order to rein in power, and to balance the relatively high threshold, two new scores are proposed:
- Arcane Potency (Po) which is equal to 10 + Magery.
- Divine Providence (Pr) which is equal to 10 + Power Investiture.
Neither use IQ as their base for checks.
Calamity Table
An alternative calamity table is provided for both Arcane and Divine magic (two types of magic in the D&D system which are being kept as is), designated by Magery and Power Investiture respectively. These tables are below. Inspiration for the Magery table has been acquired from No School Grognard‘s alternate calamity table post.
Magery Table
| Roll | Effect |
|---|---|
| 3-4 | The spell does not cost energy. |
| 5-8 | Nothing happens. |
| 9 | Until her tally is reduced to 0, the base cost of the spell is doubled for the caster. |
| 10-12 | As 9, and the caster suffers from Nightmares disadvantage (B144) with self-control number of 9 during this time. |
| 13 | As 9, and the caster has a -1 penalty to cast all spells in the same school until her tally is reduced to 0. |
| 14 | As 9 but affects all spells in the same school. |
| 15 | As 9, and as long as her tally is not 0, the caster gains the Radically Unstable Magery limitation (T26) at the -10% level. |
| 16 | As 15 but the limitation is at the -30% level. |
| 17 | The effect of 14 occurs. The caster is now considered to be in a Twisted Mana (T60) zone until her tally is reduced to 0. This zone only affects her. |
| 18 | As 17, but no longer only affecting the caster; it has a radius of 3d × 10 yards. |
| 19 | A time loop occurs in an immediate area. Every 2d seconds, time will return to the time of casting, but the spell will react differently with bizarre unintended effects. This will cease on a roll of 2-5. Until her tally reaches 0, this will always occur on the caster's spell failures. |
| 20 | The caster is severely addled and acquires a -15-point mental disadvantage lasting at least one day. After this day, the caster must make a Will-5 roll to lose it. The penalty on this roll decreases by 1 every successive day. |
| 21 | The effects of 18 and 20 occur. |
| 22 | As 21, and caster loses one level of Magery. One level is recovered every day the caster is at a tally of 0. |
| 23 | As 22, but caster loses two levels and levels are only recoverable after a HT roll. |
| 24 | Something awful happens to something the caster values, proportionate to the strength of the spell cast and possibly with the same effect. The effects of 21 occurs but the caster cannot reduce her tally for 2d days. |
| 25 | The effects of 21 occur, but the effect of 18 is in a 3d-mile radius and lasts at least 3d weeks. Caster is reduced to Magery 0 for this time. One item the caster was carrying or wearing ceases to exist permanently. |
| 26 | All magic ceases to work in the local region for 3d months. The caster is permanently warped and loses an appropriate number of levels of Appearance. |
| 27-28 | A curse is placed upon the region of casting for 3d weeks causing suffering, destruction, and death. |
| 29-30 | The caster permanently loses the ability to cast spells. The caster must succeed on a Will-5 or fall into a coma. |
| 31-39 | The effect of 25 occurs. Something permanent also changes in this region. |
| 40+ | As 31-39 but the change is now global. The caster must make a HT-6 roll or explode, dying automatically and dealing (Will + Magery) dice of crushing explosive damage. On success, the caster takes 2d damage and the effects of 19 happen but are permanent and occur on all spell rolls. |
Power Investiture Table
| Roll | Effect |
|---|---|
| 3-5 | Nothing happens. |
| 6-10 | The caster loses a point of Will until her tally reaches 0. |
| 11-12 | An intense sense of an emotion, appropriate for the deity or domain being called on, falls over everyone within 20 yards. Caster makes a Will-3 roll and everyone else rolls unmodified — those who fail are mentally stunned for 1 second because of this sudden change. |
| 13 | If appropriate, the spell is half as effective. Caster is unable to magically recover points from her tally for 1d days. During this time, all spells she casts will be at -1. |
| 14 | An effect appropriate to the deity or domain occurs. Caster is unable to cast spells for the remainder of the day and loses a point of Will during this time. |
| 15 | Any spell failures will result in a calamity until the caster's tally is reduced to 0. |
| 16 | The spell produces a mere momentary shadow of what it is intended to do. The effects of 14 occur. |
| 17 | The spell produces a bizarre, twisted effect appropriate to the deity. Caster is very aware that he has committed something to anger an appropriate supernatural being. |
| 18 | The effects of 14 and 15 occur. |
| 19 | The caster loses the ability to cast spells until her tally reaches 0. |
| 20 | As 19, and the caster is afflicted in an incredibly disastrous way appropriate to the deity or domain and gains up to a -20-point disadvantage. |
| 21 | As 20 but the disadvantage can be up to -50-points. |
| 22 | The caster must make a Pr-2 roll. If she fails, she will be immediately smitten and takes 2d damage of a type and by an effect appropriate to the deity or domain. The effects of 20 occur. |
| 23 | The effects of 22 occur but the caster does not receive a roll to negate the effect. All spells of this sphere are cast by the caster at -3 for 3d days. |
| 24 | The caster is aware that she must perform some deed. This is treated as an Obsession (9) until carried out. The effect of 19 occurs but ends when this deed has been carried out. |
| 25 | Caster loses all levels of Power Investiture for 3d weeks. |
| 26 | Caster loses at least one level of Appearance, permanently, in a manner appropriate to the sphere. The effects of 24 also occur. |
| 27 | The effects of 23 occur. The caster obtains the effects of Absent-Mindedness, Confused (9) and a -5-point Odious Personal Habit (incomprehensible rambling) until the deity or domain deems it time. |
| 28-30 | All of the forces aligned with the caster suffer a tremendous effect appropriate to the deity or domain. The effects of 27 occur. |
| 31-39 | The target permanently loses all connection with the deity or domain, losing all respective advantages or disadvantages, and gains Quadriplegic or another appropriate disadvantage of any cost. |
| 40+ | The caster must make a HT-6 roll or immediately die. If she does not die, the effects of 31-39 occur. |
Knowing Spells
Knowing spells is also a little different in this proposed system. Instead of spells as skills, which is how GURPS typically works when it comes to magic, colleges are now VH skills and any spell can be cast based on prerequisite count. Spells become Hard techniques. This is a Ritual Magic system (B242) with some slight changes: colleges have been regrouped to better be flavoured for both types of magic respectively. For Magery or Arcane Magic, colleges become schools. For Power Investiture or Divine Magic, colleges become spheres.
| College | School | Sphere | Page |
|---|---|---|---|
| Air | Evocation | Air | B242 |
| Animal | Transmutation | Nature | M29 |
| Body Control | Transmutation | Control | B244 |
| Communication/Empathy | Divination | Presence | B245 |
| Earth | Evocation | Earth | B245 |
| Enchantment | Enchantment | Craft | B246 |
| Fire | Evocation | Fire | B246 |
| Food | — | — | M79 |
| Gate | Conjuration | Planes | B247 |
| Healing | — | Life | B248 |
| Illusion/Creation | Illusion/Conjuration | Deception | M95 |
| Knowledge | Universalist | Lore | B249 |
| Light/Darkness | Evocation | Life | B249 |
| Masking/Breaking | Transmutation | Craft | M115 |
| Meta | Universalist | Control | B250 |
| Mind Control | Enchantment | Presence | B250 |
| Movement | Transmutation | Control | B251 |
| Necromantic | Necromancy | Death | B252 |
| Plant | — | Nature | M161 |
| Protection/Warning | Abjuration | Fortification | B252 |
| Sound | Transmutation | Music | M171 |
| Technological | — | — | M175 |
| Water | Evocation | Water | B253 |
| Weather | Conjuration | Weather | M193 |
Conclusion
The intention of these design changes to the GURPS magic system is to better reflavor the idea of magic in a high fantasy world, and to introduce a bit of weirdness to the idea of Arcane Magic. Furthermore, there is a bit of a want here to try and introduce something other than the typical idea of spell slots in the d20 engine.
This article has been revised for the second time on Wednesday, July 23, 2014. The threshold limit has been reduced with consideration after a series of sessions with this magic system in play.