Code:
Physical
Shadow Holy
Elemental Nature
With the arrangement mattering -- a player cannot know two opposing sources.
Then tack on hybird magic.
Physical+Shadow: Stealth etc.
Shadow: Illusion etc.
Shadow+Elemental: Necromatic etc.
Elemental: Fireballs etc.
Elemental+Nature: Storm etc.
Nature: Animals, Plants etc.
Nature+Holy: Charm etc.
Holy: Healing etc.
Holy+Physical: Blessings etc.
Physical: Enhancement etc.
A second source costs 3x as much as your first, as the incompatable magic resists you.
Hybrid sources require knowing at least one primary source they draw from. They have the restrictions of both Primary sources.
You can know two Hybrid sources, say (Physical+Shadow) and (Holy+Physical). The second Hybrid costs 2x as much as the first.
Your "second" primary and hybrid source is the lower of your two sources.
...
Now, for each rune, have a spell for each of the above sources.
Having a rune would give you the runecasting skill at POW. This can be trained up by yourself.
Being able to cast a spell requires knowledge of the source, and of the rune you are casting it with.
The Rune of Fire might do the following:
Physical+Shadow: Invisible Flame (A flame whose light can only be seen by those who touch it)
Shadow: Illusionary Flame (make an existing flame appear to move and attack)
Shadow+Elemental: Darkflame (turns a flame into Darkflame, which does cold damage)
Elemental: Flame Arrow (bolt of fire at your target)
Elemental+Nature: Heat metal (does 1 damage for every 2 points of metal armor)
Nature: Firewood (make wood burn 10 times longer and 10 times hotter)
Nature+Holy: Hypnotic Flame (dazes people)
Holy: Heal burns (efficient)
Holy+Physical: Aura of Flame (damages people who attack)
Physical: Sword of Flame (sets your sword on fire)
I'd amit it requires a completely different set of runes, and developing 10 spells for every rune. So it is a work in progress.
