Preview of some of the Sorcery part of Book 2.

Here is the intro and basic idea behind adding OD&D style spell use as if  it was first fit into traveller...

 Spells and Spell casting

Res Magicae

In Adventurer, spells are specific things that are summoned and controlled, to be used instrumentally.   Such  invocation may be of strange spirits, constrained demons, or perhaps localized pocket universes, the truth is perhaps unknowable to the mere mortal intellect. Nonetheless, it is important to understand that spells are NOT innate powers of a spellcaster; rather, the spellcaster summons and commands the spell.  In short, the spell, not the spellcaster creates the effect.

Training in spellcasting involves mastering the creation of spells and the proper command thereof.  This involves the use of mystical and rare components, combined with specific arcane gestures and phrases, precise timing, and astrological concordance, to name but a few components. The spell is thus created, and takes up residence within the spellcaster, to be expelled (cast) at will.  Casters vary in their ability to contain spells, and all spells fade out after about one day if unused.

Thus, spells operate very much like modern rounds in a weapon, which must be obtained, preloaded and specified as to type.  Similarly, once fired, spells are gone. Unlike a revolver (for instance), spells can be fired in any order, can be of various sizes and power, and (importantly) a given chamber in the cylinder cannot be reloaded for the remainder of the same day. In short: spells are bullets, the caster is the gun.

There are two basic varieties of spells:  Magical and Spiritual spells. While the procedure to use a spellcasting skill is the same for both, the need for preparation, the costs of success, and consequences of failure are very different.

Magical spellcasting skills are regular skills that allow a caster to use his willpower and secret knowledge combined with his physical and mental strength craft to specific magical spells.  Spiritual spells are those cast by priests, using the power of their deity and the casters faith and are thus differ from magical (Gnostic or Goetic) spells in important ways.

Spell preparation procedure summarized

A Magical spellcaster prepares spells at the start of the day and must preallocate all spells to be cast during the day. 

• A spellcaster must preallocate all spells to be cast during the day.
• Spell capacity in any given day is determined by the casters intelligence and skill.
• Spell capacity is equal to or less than 1/2 INT * the highest level of any one spellcasting skill

A spiritual spellcaster may cast any spell he has access to without prior preparation, and may continue casting until he fails, at which point spellcasting abilities are lost until a day and a night have passed.

Xylarthen, now a spellcaster with INT 10, and Cantrip -3 Sorcery -1 Necromancy -2 can choose up to 15 points of spells per day. (10/2 * (Cantrip) 3)

Note that the actual spells chosen are not limited by the specific skill used as multiplier.

 Spellcasting Procedure

Difficulty and cost

All magical and spiritual spells have a difficulty based on their overall power.  The difficulty of a spell is based on the spellcasting skill and generally maps the relative power and difficulty of the spells associated with said skill. The difficulty is always applied as a DM to any attempt to use that skill.  This is found in the spell listing table as appropriate.

Magical spells (only) also have a cost. Cost determines how much of a spell caster’s capacity is used by memorizing it, and the physical toll of the casting. The basic cost for casting a spell is subtracted as physical damage, and this occurs regardless of success or failure.  Where a spell allows optional costs to be paid, these are only applied if the spell succeeds.  

Spiritual spells only have difficulty. There is no basic cost to cast spiritual spells successfully, although specific spells may allow the caster to ncrease the effect (or other results) by taking damage as with magical spells.  This is always optional, even if there is no result if points are not spent ( a fizzle occurs, essentially ).

Casting:

Casting a spell is a standard skill use. Apply the difficulty of the spell type (if appropriate) , and the level of the appropriate spell casting skill, plus or minus optional or situational modifiers; throw 8+ for success.

There are no automatic success or failure rolls in magical casting.  However, if the dice result is a natural 2, apply unexpected consequences in addition to costs for success regardless of whether or not the spell roll is successful.   This doubles the cost for a magical spell, and explicitly applies to high risk spells.

Failure

Magic is inherently dangerous to a caster, above and beyond the corruption and damage to sanity that invariably accumulates through knowledge of unspeakable arts

If a casting skill roll fails, the unexpected consequences table must be consulted, and in some cases, the Terrible Consequences table is consulted.

Unexpected Consequences

Magical Spells

• If the spell fails, but the unmodified roll is 8+, any associated cost is still paid.
• If any  HIGH RISK SPELL is attempted, additional and terrible consequences occur (consult the Terrible consequences table).
• If successful, determine the effect of the spell, and  apply this as physical damage (in addition to the cost)

Spiritual Spells

• If the spell fails, the caster may not use any more spiritual spells until a day and a night have passed.
• If it succeeds, determine effect as normal, but apply this as physical damage.

High risk failures

Certain spells of both magical and spiritual origins are designated as high risk.  These are spells of great power that channel particularly corrupt, unspeakable or dangerous forms of magic.  In game terms, these are the dam-buster spells, and in most S&S genres, are terribly dangerous for the caster –which is why the caster doesn’t use them to solve all problems.

Terrible Consequences

(magical or spiritual)

If a mage fails the spellroll to cast a HIGH RISK spell the caster takes 1d6x1d6 points of damage in addition to the cost, and loses the ability to cast spells for a time. Use the lower of the two dice rolled for damage and apply to table V to determine  for how long spellcasting ability is lost.

Success

When a spellcasting roll is successful, the spell is cast with the rolled effect.  This will define much of how the spell manifests.  Effect is the final modified roll minus 8.

Spellcasting and Effect

In many spells, given a successful casting, a caster is allowed to allocate the effect points to variables such as range, targets and damage.  Range and damage are generally a direct relationship, and noted in the description.

Duration is generally determined by referencing the effect allocated with the duration type of the spell (I through VII) on the Duration table.  Spells not using the Duration table will be specifically identified.  Typically they are spells that have an instant and non-lingering magical effect, although the physical consequences may linger on.

The default duration is instant.

Targets are the number of things (loosely defined as beings or items)  that the spell takes effect upon. The final number is determined by referencing the final allocated effect on the appropriate column of the targets table.

The default for targets is 1.

Increasing effect

Many spells, especially spiritual spells, allow the caster to sacrifice Physical points to increase the effect of a successful casting.  Note that unless specified otherwise, this only applies to the effect of a successful casting; points may not be spent to modify the roll for success. Use the following table to determine the effect increase.

END points sacrificed	Modifier
2	1
3	2
5	3
8	4
12	5
18	6

Any sacrifice is made after the roll is finalized and the additional modifier is included for all final effect calculations.

Spellcasting damage due to cost or sacrifice

Damage incurred due to spellcasting costs is treated as if it were damage for all purposes except recovery unless otherwise noted. All damage due to spellcasting is recovered after a nights sleep. 

Note that this is not the same as exhaustion or actual damage, and cannot be recovered by spells, potions or any other effect that allow recovery of exhaustion or physical damage.  Only a spell, potion or artifact that explicitly affects spellcasting costs can be used to recover such points, and they should be very rare and costly to use. 

Several additional modifications to the procedure occur when casting spells in combat.  These apply to when the spell is cast, reacting to spells, taking damage while casting, and aborting spells.  They are discussed in detail in the combat section, under the action option of Spellcasting.

For purposes of damage due to spell casting (only), apply the following effects rather than the normal damage rules.

When END is reduced to zero or less the caster falls unconscious (as per combat) and excess damage is allocated to another stat. 

If both END and a second stat are reduced to zero by the same spell, the caster dies.  Otherwise, the damage becomes real, and requires normal healing.  If all three are reduced to zero, the caster dies.

Note that the sacrifice rule can explicitly allow the caster to kill himself to increase effect.  If so, the spell takes place, and the caster survives to see the final result, either mocking the victims or decrying his fate, as required.

Duration

Effect	Duration I	Duration II	Duration III	Duration IV	Duration V	Duration VI	Duration VII
0	1 round***	1 Minutes	1 Turn**	1 Hour	Half day*	Day	minute
1	2 rounds	2 Minutes	2 Turns	2 Hours	1 Day	Week	hour
2	3 rounds	4 Minutes	3 Turns	3 Hours	2 Days	Fortnight	day
3	5 rounds	8 Minutes	5 Turns	5 Hours	4 days	Month	week
4	8 rounds	16 Minutes	8 Turns	8 Hours	week	season	month
5	12 rounds	32 Minutes	12 Turns	12 Hours	fortnight	Equinox	year
6 +	18 rounds	1 hour	18  Turns	1 day	month	year	decade

* Sunrise to sunset, or vice versa.

** Whatever the basic movement turn is: 10 minutes, six minutes etc  

*** Whatever the basic combat round is: 10 seconds, 6 seconds, etc

Targets

Effect	Targets I	Targets II	Targets III	Targets IV		Targets V		Targets VI
0	1	1	1		1	1	1
1	1	2	3		4	8	10
2	1	3	5		9	27	50
3	2	4	7		16	48	100
4	2	5	9		25	100	500
5	3	6	11		36	180	1000
6 +	4	7	13		49	300	5000

Avoiding or Reducing Spell Effects

Many spells can be negated or partially avoided by an effort of will, an indomitable intellect, or simply fast reflexes.  Spells which can be avoided or reduced are noted as such. Typically, the roll will be described as a test vs. a stat, attempting to roll a total under the stat in question.   In some cases, a skill may be used, in which case it is added to the stat, rather than the roll.  If successful, the spell will have no or reduced effect for the being in question.  Any being effected by such a spell, whether by direct targeting, or being within the area of effect, may attempt the test. If the test fails, the spell takes full effect.  If an individuals test is successful, the spell is cast, but negated

or reduced for that specific target.

Learning New Spells.

A spellcaster only learns new spells if a spellcasting skill is increased or added. With each receipt of a spellcasting skill a character may choose a set number of spells from the appropriate list equal to INT -6. Each receipt of a spellcasting skill allows choice of another set of spells. If the level is gained in the career resolution, then the player simply picks the appropriate number of spells. Similalry, if the character has increased an existing spellcasting skill, or gained a new one, he becoems eligible for new spells once the skill is permanently increased.  No further spell roll is required, but learning each spell does take take a number of days  equal to  the spells cost +2. Too, the spells must be found or available in sancient magical  tomes and scrolls.  If such resources are not available, the time required is in weeks, instead of days, as the spellcaster develops them from first principles. 

Note that there is no bonus for choosing or learning  the same spell twice.  So don’t.  I tried to have one, and it breaks things.

Note that when spiritual spellcasters gain new spellcasting levels, they gain new spells automatically, with no learning period.

Xylarthen the moderately Bright is a magic User with an INT of 10.  When he first receives the skill Cantrip, he has the spellcasting skill Cantrip -1 and selects 4 spells (INT -6) from the Cantrip list: Detect magic, Hold Portal, Light and Magic Missile.  If he gains Cantrip again, he has Cantrip -2 and chooses 4 more spells: Shield, Locate Object, Knock and Levitate