This is a port of the “Ars Magica, fifth edition” magic rules into “GURPS, fourth edition”. It is aimed at translating the whole of Ars Magica spells into a GURPS system, but it does not rely on the existing GURPS Magic infrastructure. It is a complete rewrite of the magic system.
This port is a translation only. You must have both “GURPS Characters, fourth edition” and “Ars Magica, fifth edition” core rulebooks to make sense of it.
- 1 The Gift
- 2 Magical Arts
- 3 Spell casting rolls
- 4 Gestures and Words
- 5 Using Raw Vis
- 6 Spell Mastery
- 7 Warping
- 8 Aging
- 9 Laboratory
- 10 Spending character points
- 11 New Advantages out of abilities
- 12 New Advantages and disadvantages
- 13 New Skills
- 14 Spells
- 15 Sample Characters
The magic gift is purchased as an advantage with three different levels:
Subtle Gift [5 points]
- Magery 0 
The Gift [-15 points]
- Magery 0 
- Frightens Animals [-10]
- Supernaturally untrustworthy, -2 to reaction rolls with non-magical entities [-10]
Blatant Gift [-25 points]
- Magery 0 
- Frightens Animals [-10]
- Supernaturally despised, -4 to reaction rolls with non-magical entities [-20]
The magical arts, techniques and forms, are purchased as advantages with its summatory value times 5. This means that the full price of a specific level equals the sum of all levels times 5.
For instance, the “Creo 3” magical technique costs (3 + 2 + 1) * 5 points, for a total of 30 character points. An art in level 5 would cost (5 + 4 + 3 + 2 + 1) * 5 = 75 points.
Spell casting rolls
There are three ways to cast spells: formulaic spells, spontaneous spells and ritual spells. The spellcasting rolls associated with these three methods are:
Formulaic Spell Casting roll: 10 + Technique x 5 + Form x 5 – Spell Level.
Ritual Spell Casting roll: “Thaumatology” skill level + Technique x 5 + Form x 5 – Spell Level.
Spontaneous Spell Casting roll spending FP: IQ + Technique x 2 + Form x 2 – Spell Level.
Spontaneous Spell Casting roll without spending FP: IQ + Technique + Form – Spell Level.
The FP cost for a spell is its magnitude, which equals its total level divided by 5.
If a formulaic or ritual spell casting roll fails, but fails by 10 or less, the spell is still active, but its effective margin of successes, known as “penetration total” will equal 0 plus any level in the “penetration” advantage.
There are no critical successes or misses in casting spells unless the caster is powering up the spell with Raw Vis.
Spells take place in the casters’ turn initiative. A spontaneous spell can be cast instantaneously, as a reaction (i.e., an active defense), but it incurs in an additional -10 penalty.
Gestures and Words
Spells require firm gestures and words to be cast. A caster may cast a spell with more subtle or marked gestures or words for additional modifiers:
|None||-5||None||-10||0 paces (caster only)|
Using Raw Vis
Raw Vis can power up a spell. Every pound of Raw Vis grants a spellcasting roll a bonus of +2.
Every Raw Vis usage is limited to how much Raw Vis a mage can use in a single action as per the rules in AM82.
Spell Mastery is purchased as an advantage that affects a specific formulaic spell. Every level in this advantage allows the mage to “purchase” a different ability for that specific spell.
Every spell mastery level costs 2 character points.
The specific abilities that can be purchased are listed in AM87.
Warping is a 0-point disadvantage that is gained through various means as described in AM167. The character must take note of his total warping points as well as the warping “score”, which is the actual value used to modify certain rolls, namely twilight and aging.
Twilight Roll: Concentration (IQ/A) skill level + Vim Level – Warping Score – Warping points gained in this action – Local magical aura.
Twilight Comprehension: (Enigmagic Wisdom (IQ/VH) skill level or IQ-4 level) + Vim Level – Warping Score.
The “Ars Magica” aging mechanic at AM168 is completely different than that of GURPS, and in order to preserve the feel of the setting, it should also be ported along with the magic rules.
Aging Roll: 3d + (Age / 10) + Living Conditions Modifier – Longevity Ritual modifier.
The aging roll result is checked in the table below:
|8 or less||No apparent aging.|
|9 a 13||Apparent aging increases by 1 year.|
|14, 15||-1 to ST and apparent aging increases by 1 year.|
|16 a 18||-1 to HT and apparent aging increases by 1 year.|
|19||-1 to DX and apparent aging increases by 1 year.|
|20||-1 to IQ and apparent aging increases by 1 year.|
|21+||Crisis and apparent aging increases by 1 year.|
Crisis Roll: 3D + (Age / 10).
|13 or less||Bedridden for a week|
|14 - 16||Bedridden for a month.|
|17, 18||Minor illness. HT + 5 to survive, or a CrCo 20 spell.|
|19, 20||Serious illness. HT + 2 to survive, or a CrCo 25 spell.|
|21, 22||Major illness. HT to survive, or a CrCo 30 spell.|
|23, 24||Critical illness. HT –2 to survive, or a CrCo 35 spell.|
|25+||Terminal illness. HT –5 to survive, or a CrCo 40 spell.|
GURPS’s “Longevity” advantage is altered in these rules. It grants the target a -3 modifier on aging and crisis rolls, which roughly equates to 30 more years of life.
Lab Total: Thaumatology skill level – 10 + Technique + Form + Magic Aura.
Max Raw Vis usage at every season: (Thaumatology skill level - 10)
Spending character points
Players can spend their character points to learn new spells or improve their arts. The character point cost for a spell equals its total level divided by 10, rounded up.
New Advantages out of abilities
Parma Magica [3 points per summatory level]
Parma magica is purchased as a summatory advantage that costs 3 points per summatory level. This means the first level costs 3 points. The second costs (2+1)*3 = 9 points. The third costs (3+2+1)*3 = 18 points, and so on.
Each level grants the mage a magic resistance of 5 which does not affect the mage’s own spells.
Penetration [1 point per summatory level]
Like “parma”, penetration is a summatory advantage. Each level in this advantage grants the mage 1 extra “penetration” per spell. This increases the effective margin of successes of his rolls if the spell was successful, causing his spells to be harder to defend against. This does not prevent the mage from spending FP when his formulaic spells fail for 10 or less.
New Advantages and disadvantages
This is a translation of the “virtues” found in AM40 and “flaws” found in “AM51” into GURPS advantages. When applicable, the granted bonus or penalties have been translated as well. When not noted, assume the listed bonuses or penalties are the same as in AM.
Some advantages have clear translations in GURPS settings (such as “common sense”, “famous” or “intuition”). These virtues or flaws are not listed below.
Unless noted, bonus and penalties must be translated “as-is”. For instance, the “Inventive Genius” virtue grants a +3 bonus (or +6 when experimenting) to lab totals when inventing new spells, items and potions. As an advantage, it also grants a +3 (or +6) to lab totals under these conditions.
Virtues => Advantages:
Flaws => Disadvantages:
It is recommended that a character cannot gain more points from hermetic flaws than half the points spent on hermetic arts and spells.
Finesse (DX/E), defaults to DX - 4.
Concentration (Will/A), defaults to Will - 5.
Enigmatic Wisdom (IQ/VH), no default.
Building spells follows the same rules with the same parameters as in Ars Magica. Some specific system-related mechanics must be noted.
When designing damage-dealing spells, convert each +5 to 1d of damage.
If in doubt, the base level for a damage-dealing spell usually equals 5 times the number of dice of damage minus one level. If the damage is caused by an unnatural shape, add 1 level to the base.
When designing healing spells, restored hit points are converted from wound descriptions as follows:
- Light Wound: 1 HP and the target’s wounds are stabilized.
- Medium Wound: 3 HP.
- Heavy Wound: 6 HP.
- Incapacitating Wound: 12 HP.
Non-Instantaneous non-ritual healing spells are not cumulative. This means that if the maga is casting a spell which heals a target for X HPs for a specific duration, and the target takes damage during that time, then the target can only be further healed if another, stronger healing spell is cast upon it, or when the duration of the first spell wears off.
Likewise, non-instantaneous non-ritual healing spells can heal a target beyond its maximum HP boundary. Thus, if a maga knows a spell that grants X HPs for a specific duration, they could cast this spell at the start of combat, and the target would benefit from the added hit points, which would be lost before any "actual" hit points. Temporary hit points beyond the maximum cannot be healed by natural healing.
If the temporary hit points of a non-instantaneous non-ritual healing spell are lost, the spell is still ongoing and will not be cancelled.
Damage Resistance Spells
When a spell would grant damage resistance to a target, convert each +1 soak in 3 points of DR. If the DR is form-specific, such as “only against fire”, then each +1 soak equals 6 DR.
Spells that grant or remove advantages or disadvantages
Many spells may grant or remove advantages or disadvantages to a target. The base level of such spells cannot be lower than half the number of granted (or removed) character points. If the description of such spells would allow for a lower base level, use the advantage or disadvantage cost divided by two as base. This guideline can also be used for spells that alter a character’s attributes.
No spell may increase a target’s IQ above that of the casting mage.
Derived attribute bonuses do not stack with main attribute bonuses. For instance, if a character is under two spells, one which grants ST+1 and another which grants HP+2, his total HP increase is +2, not +3.