Ritual Path Magic
Arcane magic uses a slightly modified version of the Ritual Path Magic system (found in GURPS Thaumatology – Ritual Path Magic). Each path corresponds to one of the Arcane Realms.
There are eight paths instead of nine, corresponding to the eight Metarealms. Crossroads is split into Space and Time. Body is known as Life. Undead is called Death. Mind affects both organic minds and sentient computers. Spirit is split among all the other paths, depending on the type of spirit being dealt with. Magic is not a seperate path skill; Path of Magic effects use the base Thaumatology skill.
Magery does add to Path skill and Thaumatology. Additionally, the Ritual Adept advantage only costs 20 character points.
The mage determines the effect of the spell. The necessary mana cost is determined by the Magic Modifier Tables; add the effects, modifiers, and multiply by the greater effect multiplier. The thaumaturge can gather ambient mana, tap their own mana reserve, tap their or another’s life force, or use another external mana supply (like Powerstones, Paut, or mana batteries). Once the mana acquired, the arcanist makes a skill roll with their Path skill (or the lowest Path skill of all Realms involved) and any relevant bonuses or penalties.
A spell can be made conditional with a Lesser Control Chance effect. Charms can be created, but they are considered a form of Enchanting, and Elixirs are considered a form of Alchemy, and expire based on those skills.
A mage has a personal mana pool with a base maximum of (Will + Fatigue)/2 + Magery*3. This can be increased at a cost of 3 character points per point of mana. A mage regenerates mana points equal to their Magery every hour while not casting or concentrating on spells. They can also restore their mana using Thaumatology to gather ambient energy.
Mages can learn individual spells as Hard Techniques linked to the associated Path skill. A mage can often learn spells in spellpads (datapads specially built and programmed to hold spells), and increase their proficiency through practice, or they may invent and perfect their own. They may also take the Ritual Mastery perk for a specific spell, or Tradition for a specific tradition or class of spells.
Specially-prepared digital grimoires known as spellpads can provide an additional bonus. Physical written grimoires are even more powerful, but quite rare, and usually only used for rare, powerful rituals.
Staves, wands, and rings can be made with materials (particularly metals, wood, and gemstones) that naturally resonate with the Metarealms, increasing the Thaumaturge’s spellcasting power. A wand or staff made of resonant materials that increases the effective Path skill or Magery, and thus the energy gathered and the margin of the final skill roll. A wand or staff can also deliver touch spells, and increases the range of a spell cast through it by its length. Rings (and sometimes wands) can have a bound spell, allowing the mage to cast it without mana.
By using traditional trappings that relate to the effect of the spell and/or the Metarealm it calls on, a thaumatuge can reduce the energy needed to power a ritual. These can be resonant materials, colors, or other associations. They can also cast the spell in a sacred, high-mana, resonant, or other place of power, increasing the amount of ambient energy collected.
Multiple mages can form a circle to cast a spell than none could cast on their own without great risk. To cast collectively, all members of the circle must have Ritual Adept, or else the entire circle must cast at the non-adept speed. For each roll to gather ambient energy, all members of the circle sum their margins of effect to determine the mana gathered. Individual failures contribute a negative margin to the total, but the step is only an overall failure if the total margin is 0 or negative. An individual critical failure still contributes a margin of -1 even if the mage’s effective skill is higher than 18. An overall critical failure occurs if there are more individual critical failures than successes, or if the margin of failure is greater than 2 times the number of participants. An energy gathering stage counts as a critical succ ess if all participants roll a critical success, or if the total margin of success is greater than 10 times the number of participants. After the energy is gathered, only the leader makes the final skill roll to cast the spell.
Other Magic Systems
Thaumaturgy is just one form of magic. Although arcane magic is the most widespread, there are other magical arts that characters can learn.