Here is an excerpt from Dragons at Dawn, the Arneson legacy system. This gives the magic rules, or system, it's a nice nutshell, and I think it would be a cinch to drop it into my Eldorath Campaign pretty much wholesale.
WIZARD
Wizards are humans who create spells in laboratories and throw magic. Wizards gain advantages in all mentally based Saving Throws. They receive a +1 at level 4 (hero) and a +2 at level 8 (superhero) to all Saving Throws vs. Brains (Spells in DnD) and all spell saves vs. Constitution. Wizards can see in the dark as if in daylight and can cast Wizard Light, Lightning bolt and Fireball spells at will.
MULTICLASSING
“Because we didn‟t have character classes then, every player had to play it the way they wanted to.” Dave Arneson, Mortality radio interview, July 9th, 2004.
There are no restrictions on characters switching their class between adventures. Indeed doing so allows players to create more customized characters. The multiclassed character must stop advancing completely in one class and switch entirely to the new class at 1st level. All experienced gained will be applied to the new class. They will not lose their old abilities and can use them as before with no new penalties, but they are subject to the appropriate class restrictions of BOTH old and new classes. Regardless of what skills they use or activities they engage in during an adventure, they will be assumed to be practicing the new class skills and abilities when they are not directly involved in adventure situations. Indeed, the same is assumed of all characters, whether multiclassed or not. Multiclassed characters will not receive any additional Hit Dice or Hit Point Values until they have advanced in the new class to a point where they would receive more HPV and HD than they currently posses, or they switch back to their old class. A player may switch classes, add as many classes as they like, or switch back to a former class as many times as they like, however character age may well begin to take its toll before they get very far if they switch often.
SPELLS
Wizards can channel raw magic energy to make Wizard Light, Lightning Bolts and Fireballs. This magic may be thrown at will but requires the Wizard to make a Saving Throw versus Constitution for the spell to successfully trigger. Failure of the Saving Throw means failure of the magic and causes the Wizard to collapse with exhaustion which will last for 2d6 turns. Note that, for Wizards, these Throws apply only to these magic energy spells and not material based spells.
In the Basic Game, all others spells are tied to physical things made of special ingredients, not magic energy or enchanted words. Spells are often found in the form of potions in bottles or vials, gasses trapped in delicate glass balls, powders in paper tubes, and the like, including spell scrolls written with magical ink made from distilled superberries. Spells must be employed in a particular fashion to cause the spell effect and, except for some potions and powders that may have multiple doses, are generally used entirely upon application.
Regardless of the form the final spell is in, several ingredients are required. These ingredients are often, (but not always) hard to come by and expensive. They may range from the hair of a white dog born at midnight to stale bread. The
exact ingredients of each spell are
not specified in these rules for several reasons. First, it is not essential to the game to know the specific ingredients used in the preparation of a spell as it can be assumed the Wizard uses his treasure to purchase what he cannot procure himself at a total cost of 100 gold pieces per level of the spell. Second, we do not know what exact ingredients, Dave Arneson used for his spells. Third, and perhaps most importantly, in campaigns where lists of specific spell components are desired, they must match the world and biome the campaign is set in.
Whatever their final form and
ingredients, spells must be
prepared in a laboratory. There
is a 35% base chance the finished
spell will be a dud and not work
when employed. This failure rate
increases by 10% per level of
complexity of the spell, (i.e. level II
- 45%, level III - 55%, etc.), -5%
per level of any Wizard who has previously completed that particular spell successfully. Thus a 1st level Wizard who has already completed a 1st level spell now has a 30% chance to fail to make the same 1st level spell. Likewise a 5th level Wizard who has already completed a 1st level spell and a 3rd level spell
now has only a 5% chance of failure when making the same 1st level spell and a 25% of failure when making the same 3rd level spell, but would have the standard 35% chance and a 45% chance respectively to complete a new 1st and a new 3rd level spell. These percentages can be greatly modified by learning how to make a particular spell under the tutelage of an accomplished teacher. A high Dexterity score will also improve a Wizards chance of creating a successful spell by 5% for Dexterity scores of 8 or 9 and by 10% for a Dexterity score of 10.
Spell level reflects both the complexity of the spell and the minimum level of the Wizard who may attempt to safely create the spell. Wizards cannot make spells above their level, although they may attempt to cast them – see Improper use of Spells below.
Prepared spells may sometimes be purchased at a minimum of 300 GP times the spell level. Wizards frequently hire out their spell making services to wealthy patrons as a way to finance their own ambitions.
Upon completion, spells will have the Alignment of the Wizard who made them. It is not possible for a Wizard to make a spell or any sort of magic item of a different Alignment from their own.
Generally, a Wizard will not know if a spell has been completed successfully until it is actually employed. Thus if a referee does not know the success or failure of the production of a given spell ahead of time, the above chances must be rolled against when the spell is employed. If the level of the Wizard who made the spell is unknown assume the standard chances of failure modified in this case by 5% per level of the caster for spells they have cast or made before.
When a Wizard acquires a spell they did not make, they may safely employ it if it is of their level or less and they have knowledge of how the spell is to be triggered. Again, however if the referee does not know the success or failure of the production of a given spell ahead of time, the standard chances must be rolled against.
Length of time to make a spell is one week for level 1 spells, one month for level 2 spells, and 1 year for level 3 and higher. A Wizard may work on any number of spells at one time provided they have the components and the workspace.
Augmentation
Spells may be augmented by making them as if they were of a higher level. Augmentation increases the effect of the spell by 20% per higher level but requires the added time it takes to make a spell of the target level and the expense of 20% per level added also. Usually, Wizards cannot augment a spell to a level above their own, unless they commit a great deal of time, and expense to the endeavor. Through such intensive research it is possible to learn how to effectively reduce the complexity (level) of a spell so that Augmentation of the apparent effect of the spell is possible beyond the normal level of the Wizard.
Improper Spell Use
Any non Wizards (including Elf Mages) who attempt to use spells do so at some peril. The same applies to Wizards who attempt to use spells above their level. There is a 10% chance for non Wizards, and a 20% chance for Wizards, that the spell will actually work, regardless of the spell level, but there is also a
Spells are aligned the same as their creator. Spells can only be used by Wizards of the same Alignment as the spells creator. Any attempt to use a spell of a different Alignment requires an immediate Saving Throw vs. wisdom at minus 3. Failure of the Saving Throw means the Wizard will suffer the effects described for touching magic items of a different Alignment as described below. The spell will trigger normally if the Saving Throw is successful.
I
Boost Reaction Time Darkness
Read Emotions Resistance to Fire Wizard Light
X ray Vision
II
Animal Obedience Cause Morale Check Detection
Evil Detection Illusion
Locate Object Speak with Animals
III
Concealment
Detect and Open Secret Doors Fireball
Fly
Lightning Bolt
Move Silently
Protection against Magic Protection against Lycanthropes Protection against Undead Speed
Spells by level
IV
Appearance Extra-sensory Perception Invisibility
Scrying
See in Darkness
Shape Changing
Size
Speak with Plants
V
Cause Panic
Combat Increase Conjuration of an Elemental Decay
Raise Morale
Strength
Teleport
VI
Brains Increase Clone
Food
Heroism
Human Obedience Invulnerability Paralyze
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