Ars Magica House Rules

From The Z-Team Wiki
Jump to: navigation, search
Ars Magica: Nova Semitae Saga
Game Start
Anno Domini MCCXX, hiems
A.D. 1220, winter
5 Neanne 1, Hiems
Game Year
Anno Domini MCCXXXV, hiems
A.D. 1235, winter
6 Aulus 2, Hiems
Magi of Nova Semitae
Geoffroy de Dreux of Jerbiton
Joshua Levi of Verditius
Magni of Flambeau
Obscurus Ignis of Flambeau
NPC Magi
Aulus · Neanne · Fr. Thomas
Aline · Ysabelo

Hermetic Status
Lady Angharad ferch Madog, Princess of Powys Fadog
Ritter Sigmund, German ex-Crusader
Sir Daniele d'Audrieu, Norman merchant
Sir William Cornwell, English ex-Crusader
Other Characters
Covenfolk · Agents
The Redcaps · Notable NPCs
Chart of Languages Spoken
Notable Animals
Hortense of House Bonisagus
The Covenant
Covenant Charter · Membership Record
Record of Offices · Covenant Service
Council Voting Records · Hermetic Politics
Stonehenge Tribunal
Mundane Geography · Mundane Politics
Village of Melverley · Melverley Castle
Village Laws · Village Rumors
Medieval Farming
Covenant Resources
Covenant Library · Varana's Tomb
Hospital · Hospital Library
Vis Sources and Stores
Covenant Magical Items · Mundane Wealth
Classes and Training · Covenant Experts
Covenant Mechanics
Ars Magica House Rules
Ars Magica Expanded Notes
Campaign Log · Loose Ends
Ars Magica PC Reference
Player Resources (PDFs)
Experience Point Worksheet
Character Sheet (Variant 1)
Character Sheet (Variant 2)
Experience Point Chart

Core Mechanic Rules

Stress and Quality Die Minimums

5th edition reintroduced the notion of a stress die without negative results. This is what older editions called a "quality die."

The purpose of stress and quality die are to make the 1d10 rolls much more noticeable. However, it is possible to roll a '1', then a low number to achieve a pitiful result. As such, the following floors (minimums) are used:

Number of 1's rolled Minimum Result
1 10
2 15
3 20

Additional 1's rolled add +5 to the minimum result when the non-1 is finally rolled.

"Take 5"

This is a concept introduced in the d20 system. If an action, spell or other roll takes place in a non-stressful situation (i.e. a simple die roll), a character may "take 5" on the roll. That is, they may assume they rolled a 5 on their die roll to calculate results. The player has the option of rolling, if they so desire. This makes it so that routine applications of skill aren't tested constantly.

Characteristic Changes

The Agility characteristic is merged with the Dexterity characterstic. Whenever Agility is used in a calculation, use Dexterity instead. In its place is the 'Luck' characteristic. Luck will be used for random occurrences, ill timing, and serendipitous events.

Character Generation

Baseline Skills

After chargen is completed and all xp is spent, magus characters must add the following:

  • Add (Organization) Order of Hermes Lore 1. This represents a bare minimal amount of knowledge about the Order passed on from your master and your apprenticeship covenant. Ex Miscellanea magi may potentially forgo this. If the magus already has this skill at least at 1, the magus gains 5 xp to spend anywhere else.
  • Add (Organization) House (Magus' House) Lore 1. This represents a bare minimal amount of knowledge about a magus' house learned from interactions with his or her master during apprenticeship. If the magus already has this skill at least at 1, the magus gains 5 xp to spend anywhere else.
  • Add (Master's Covenant) Area Lore 2. This represents a minimal amount of knowledge that was accumulated at the magus' apprenticeship covenant. If the magus already has a score of 2 or more, the magus gains 15 xp to spend anywhere else. If the magus has a score of 1, then it is raised to 2 and gains 5 xp to spend anywhere else.

If the magus was born in one place but apprenticed elsewhere, then:

  • Add Speak (Language local to apprenticeship covenant) at 4. This represents 15 years of being exposed to another area's language.

Companion and grog characters must add:

  • Add Area Lore (Origin City/Town/Village) 2. This represents minimal knowledge of the area the character was raised in. covenant. If the character already has a score of 2 or more, the character gains 15 xp to spend anywhere else. If the character has a score of 1, then it is raised to 2 and gains 5 xp to spend anywhere else.

Hermetic House Virtues

  • A Flambeau magus may take one of the other Virtues listed in the House Flambeau fighting styles instead of the typical Puissant Virtues
  • A Tremere magus may take Skilled Parens instead of Minor Magical Focus (Certamen). Alternatively, the magus may take an additional Minor Magical Focus. This is the only exception to having only one Magical Focus.

Laboratory Texts

Starting magi are assumed to have untranslated laboratory texts for all the spells they learned during their Apprenticeship.

Enchantment Research

When a magus undertakes the Enchantment investigation lab activity, a laboratory text is produced as usual. However, this lab text can only be used to assist *the next* Enchantment investigation lab activity on the item. This lab text provides a Similarity Spell bonus equal to the InVi Investigation Lab Total.

This is to encourage collaboration between magi investigating an item by allowing them to hand off previous work; this explains how a magus can 'pick up' at later spot and not tread the same ground. The lab texts need to be translated as normal to be usable by magi other than the original researcher.

Skills Interpretations

Area Lore

Main Article: Area Lore Rules

Area Lore is a useful ability to have, yet there are questions about how much you know given the size of the area selected. I've included expanded notes on how much a character would know.

Virtues and Flaws


Rather than have to keep track of all the partial experience points as you gain them, record two totals on your character sheet: Raw Experience (Effective Experience), where Effective Experience is 1.5 times Raw Experience, rounded down. The Effective Experience total is used to calculate the Art or Ability score. e.g. A Flambeau magus with Affinity (Ignem) starts with 15 xp in Ignem. The player writes 15 (22), which means the magus has an Ignem score of 6.

Magical Focus

Per the Character Generation section above, a Tremere magus may take a Minor Magical Focus in addition to their free House Virtue. This is the only exception to having more than one Magical Focus.

New Virtue: Strong Writer

You write about magic with great speed and enthusiasm. You translate spells from shorthand at (Speak Latin x 30) levels per season, and copy (Profession Scribe x 90) levels of translated lab texts per season. All summae and tractatus you write have +3 Quality. When writing a summa, you accumulate two more levels person season. When copying a summa, you accumulate (8 + Profession Scribe) points per season if copying carefully or 24 + (3 x Profession Scribe) points per season if copying quickly. Finally, you can benefit from one additional Correspondence per year (granted at the end of the year), as long as the topic is an Art or an Arcane Ability.

This Virtue is not available to current magi, but may be developed for future magi and apprentices.


Flavoured Vis

Vis may be "coloured" or "flavoured" in addition to, or in place of, standart Arts. For example, what appears to be a pawn of Mentem vis, may function as 3 pawns of vis for the purpose of summoning spirits. Alternatively, it may be a 3 pawn vis source only for summoning spirits, and not work for Frosty Breath of the Spoken Lie. This keeps the mystery in magic.

Flavoured Auras

As with Flavoured Vis, Auras may be aspected to work better, worse, or only for a very specific use. Auras may carry multiple such modifiers. For example: A magical aura in a swamp may rate as Level 2, but add +4 to disease-type spells. A level 1 magical aura near a volcano may add +6 to fire-type spells, but penalize Aquam spells by -6.

Parma Magica Folds

As the characters start the saga, a new "fold" (method to use Parma Magica) is being propagated throughout the Order. It is an improvement on the original parma magica in that it can partially block the magus' Gift from affecting others (primarily mundanes). While using this fold, a magus can blunt the effect of his Gift by sacrificing the effectiveness of Parma Magica as a magical barrier. While raising their Parma Magica at dawn and dusk, a magus can reduce their Parma Magica score by 2 points in exchange for a 1 point reduction of their Gift penalty. For such reduction, the magus' Parma Magica is reduced for the purposes of calculating magical resistance. (The magus still adds the his Form score.)

e.g. A Bonisagus magus with the regular Gift (-3 social penalty) has a Parma Magica score of 3. He reduces his Parma Magica by 2 to 1. After the Parma Magica ritual is done, the magus is now -2 to social situations and his base magical resistance is 5 (Parma Magica of 1, times 5).

Spontaneous Spells and Form & Effect Bonuses

In keeping with the Focus & Effect (F&E) charts printed in the ArM5 main book or any subsequent books, a magus may use items to add a sympathy bonus to spontaneously casted spells, to help them achieve more powerful effects. For example, while casting a spontaneous spell to make oneself invisible, using a quartz will add up to +5 to the spell casting roll (before division). These F&E bonuses are capped by the magus' Magic Theory.


Generally speaking, a ward must penetrate in order to be effective. However, there are two exceptions:

  • If the ward matches both the Realm and the Form of the creature, then it does not need to penetrate.
    • Example: Ward against Faeries of the Wood would protect against all woodland faeries and would not need to penetrate their Magic Resistance. It would be ineffective against Magical or Infernal woodland creatures, however. Ward against Woodland Threats would protect against all supernatural woodland creatures, but would need to penetrate.
  • The Aegis of the Hearth being derived both from the Parma Magica ritual and Mercurian practices is something more than a Ward and does not need to penetrate in order to be effective. This reinforces the notion that Hermetic magic is superior to many other types of magic.

Magic and Nourishment

Magically created things do not nourish. As per the CrAq guidelines, water created temporarily does can quench thirst but has no lasting benefit. Food created temporarily from Herbam (as per the CrHe guidelines) and Animal has a similar limitation, quenching hunger but offering no lasting benefits. It particular, such food and drink does not stave off deprivation.

While seeds (calves, piglets, or so on) can be made to magically-grow faster than usual, such magic is delicate and will tend to induce Warping in those who consume the produce. Only relatively minor coaxing, such as that provided by The Bountiful Feast, can circumvent this drawback.

Things created by momentary Creo rituals are mundane, and as such can nourish and do not induce Warping, although they may bear the caster’s sigil.

The RAW says that magically created food is nourishing “for as long as the duration lasts”, which contradicts the Aquam and Herbam guidelines and is difficult to run in-game. Saying it doesn’t nourish is simplest to apply.

The second proviso is required to prevent exploitation of the RAW to create a lot of produce by repeatedly planting seeds, growing them instantly magically (using CrHe guidelines), and then harvesting the produce and repeating the process.

Lab Activities


A magus may attune an invested device as his talisman in the same season as its preparation/opening (or in the last season of creation, for multiple-season projects) without any additional costs. An existing device may be opened for attunement and 2 casting bonuses in a single season.

Fixing Arcane Connections

It requires 1 month of lab work (down from 1 season) to fix an arcane connection. This costs 1 Vim Vis per fixed arcane connection. This change will allow magi to fix more arcane connections easily either as a batch, or if they're willing to take a hit on a lab activity.

Library and Scribing Rules


Although commentaries are treated as tractatus for the purpose of writing, copying, and reading, they do not count against the number of tractatus on a subject that a character can write.

Translating Laboratory Texts

A magus may translate lab texts whose magnitude is less than or equal to Magic Theory + 2 without having to go through the initial 'understanding the magus abbreviations' process (See paragraph 1, p. 102 under Translating Lab Texts.) However, if a lab text is higher than this, then a magus can go through the full process including lab totals to understand a magus' abbreviations prior to translating.

Enhanced Writing Rules

Beta rules, subject to tweaking

Many of the books in the library have qualities that exceed the standard book rules. This was originally for flavor, so that some books would express quirks or additional characteristics of the author. There were no formal rules to allow for this, but as PC magi and other academics progress, this seems like something they might want to do.

Profession Scribe is the skill that will allow this. A specialization of ‘original compositions’ will allow a +1 specialization bonus.

Writing Roll: Communication + Profession Scribe stress roll

Having either Good Teacher or Strong Writer adds +3 to this roll. Having both does not double this bonus; only one applies.

Generally speaking, a Writing Roll of 12+ is required to ‘activate’ the additional options. Botches not only disallow the option, but reduce the quality of the work by 1 per botched die as your attempts to expand your work devolve into a self-referential cul-de-sac that confuses readers instead. A higher writing roll may activate additional effects.

There are several variants of that can be done:

Embedded Skills Tractatus

Example in library: Ex Nihilo (Creo Summa with Profession Gardener tractatus); or And the Magus Was Surprised (Finesse Tractatus with Culte Duello Lore tractatus)

While writing a SUMMA or TRACTATUS of an ART or ARCANE ABILITY, make a Writing Roll of 12+ each season. If the roll succeeds every season, you can ‘embed’ a Tractatus in the margins that a reader can reread after they finish the reading the main subject. The tractatus must be a skill that complements the subject/context of the summa.

A Writing Roll of 15+ each season increases the Quality of the Tractatus by 2.

Complementary Arts

Example in library: Igni Ferroque (“Fire and Iron”)

When writing an ARTS SUMMA or ARTS TRACTATUS, make a Writing Roll of 12+ while writing. If the roll succeeds every season, you can combine two Arts Summa or two Arts Tracatus into one book. This assumes that both books are written with the other subject in mind so that callouts to the other work are embedded in the work. This helps tie the works together, but is tricky to do. However, if done right, this allows a reader to benefit from a +2 Quality boost if reading the other half within 1 year of the first half.

Advancement Rules

Changing Specializations

A player may change the specialization of a given skill when enough experience points have been accumulated to increase the skill. This change also has a roleplaying requirement to justify the change.

Language Exposure Rules

Characters can pick up a new type of language exposure experience that stacks regular exposure experience to represent picking up the local language. Characters can pick up a maximum of 1 xp per season in a language spoken by the locals of their area. If there is more than one local language, the character can pick which one to gain the xp in. You cannot learn to speak better than the prevailing average of the area. Unless otherwise indicated, a character may only earn enough experience to gain level 4 in a language.

This language exposure experience is limited by personality traits like xenophobic, proud, prejudice, reclusive, or any other trait that would preclude the character from wanting to pick up another language. For every point in these personality traits, one season of this language exposure experience is lost, starting with the Spring season. It is possible, with enough negative personality traits, to not gain any local language experience.

e.g. A character living in England without any negative personality traits would gain 4 xp in Middle English, at 1 xp per season.

A character with Reclusive +3 would only gain 1 xp in Middle English per year in the Winter season.

Due to Nova Semitae's location and ethnic makeup, the following are considered "local languages":

  • Middle English (all)
  • Middle Hebrew (all)
  • Welsh (all)
  • Norman French (those who deal with the local nobility on a regular basis)
  • Latin (apprentices)

Area Exposure Rules

Every year (in the Winter season, but not for the first Winter season), each character earns 2 xp that must be spent Nova Semitae/Melverley Area Lore, until a score of 2 (15 xp) is reached. This rule encourages some verisimilitude in that characters gain the Abilities to represent basic knowledge of their surroundings. The extra XP are free because forcing characters to invest XP in increasing Area Lore diminishes their already limited Ability lists.

Session Experience Points

Every session, each magus or companion that was played receives a number of Adventure experience points. These must be spent on skills, Arts, or spells used during the adventure.

This Adventure experience can be "stacked" with any other source of experience so as not to discourage magi from leaving the lab.

Spell Mastery Rules

Spell Mastery Experience Points

The first time a formulaic spell is cast in a session earns the magus 1 xp for the purposes of mastering the spell.

Additional Spell Mastery Abilities

These spell mastery abilities are listed in Houses of Hermes: True Lineages, pp. 99-100 for House Mercere, or in Houses of Hermes: Societates, p. 33 for House Flambeau. However, given how few magi there are in that House, I'm making these available to the Order at large. These add to the existing Mastery abilities on pp. 86-87 of the main rulebook.

This special ability may only be taken for General spells. You may use your mastery score and all the special abilities associated with this spell whenever you cast the same spell at a different level.

When casting this spell, you may use vis to increase the Range, Duration, or Target by one magnitude for each pawn spent. You may not boost the Duration to Year or the Target to Boundary unless the spell is already a Ritual.

You may use ceremonial methods when casting this spell, increasing the casting time and adding your Artes Liberales and Philosophiae to your total. This cannot be taken for Ritual spells, which always require ceremonial casting.

When casting this spell, you may suppress or alter your sigil, to hide your identity or make the spell appear to have been cast by someone else. Since this actually changes your sigil, it is impossible for others to recognize you from it, though magi might be able to recognize that a fake sigil is not genuine. When you mimic the sigil of another magus, you may add your Spell Mastery score to the roll that determines how difficult it is to recognize.

You may end the effects of this spell at will, simply by concentrating on it. For timing and concentration purposes, treat this as if you were casting the spell. If you are distracted and fail your Concentration roll, you may try again in another round.

Add the caster's Mastery score to all Concentration rolls related to this spell. This helps her maintain spells of Concentration Duration amid the chaos of combat or while maintaining another spell (see the Concentration Table, ArM5, p. 82)

You understand the theory of this spell so perfectly that you may add your spell mastery score to your Lab Total when designing effects that are similar to it (see Similar Spells, Ars Magica 5th Edition page 101). This is in addition to the standard similar spell bonus.

The first time in a session that you botch a roll for this spell or fail it by exactly one point, you gain five experience points towards mastery of this spell. The roll must come up naturally in the course of the story.

This spell is less exhausting for you. If it is a Ritual, you lose normal Fatigue instead of long-term Fatigue when casting it, and half as many Fatigue levels, rounded up (but always at least one). If it is formulaic, you never lose Fatigue levels because of a low casting total, even if the spell doesn’t succeed.

You may give control of this spell to another person, who is subsequently treated as the caster, or to an object that holds the spell like a charged item for its duration and casts it if an appropriate target comes into range. This cannot be taken for Ritual spells.

Familiar Advancement Rules

Per Realms of Power: Magic, familiars (and other magical creatures) suffer a penalty equal to their Might score to the Quality of all advancement sources. This is modified in the following way:

  • Familiars may be taught by their magus normally, with no penalty. This means a magus may have a very well-trained familiar at the cost of developing his or her own abilities. But this is a fair trade-off.
  • For all other advancement totals, the familiar suffers the normal penalty (equal to their Magic Might), but this is lessened by the Silver Cord. Reduce the penalty by (Silver Cord score x 3). This can only eliminate the penalty, not add a bonus.

Gifted Children

Rules adapted from Atlas Games forum thread "You're what?" and a Durenmar essay, "Hermetic Babies" by Shannon Appel.

  1. Determine Number of Children
    Roll a stress die:
    1: Possible "botch", roll 1 Botch die to confirm (more may be added if circumstances fit)
    0: Botch: Birth results in hermaphrodite, child with animal features, or other unusual features
    1-9: Single birth
    2-9: Single birth.
    10+: Possible "crit", resulting in multiple births:
    2-10: Single birth, see 2-9 above.
    12-22: Twins
    24+: Triplets
  2. Determine Gender of Children
    Roll a simple die for gender:
    If even, female
    If odd, male
  3. Determine Gifted status
    At the time of birth roll a stress die.
    a 15+ the child has a Minor Supernatural Virtue.
    On a 18+ the child has a Major Supernatural Virtue (or multiple Minor Supernatural Virtues)
    On a 21+ the child has The Gift
    + the Aura modifier for the aura in which gestation occurred.
    +2 for each parent with a Minor Supernatural Virtue
    +4 for each parent with a Major Supernatural Virtue
    +6 for each parent with The Gift
    Note that Supernatural Virtues will be influenced by the Aura at the time of conception.

Hermetic Status

Beta Rules, subject to revision

Main Article: Hermetic Status

To broadly gauge one's standing in the Order, a new attribute called 'Hermetic Status' is introduced. This is a number from +5 to -5 (similar to Attributes) and increases or decreases in a pyramidal fashion, much like Attributes. The positive and negative values are detailed in the article linked above.