Just a note: any numbers here are largely based on AD&D 2e, though they'll fit fine in 1e or OSRIC without any trouble. Labyrinth Lord or Swords and Wizardry would require a bit of fiddling, or simply a new chart to be put together. A project for a different day perhaps.
Also be warned that I'm typing this up from the office from notes scribbled on napkins from the Black Barn Restaurant in NJ where this lunatic idea hit me over a bowel of good chili, so don't expect any real coherence here in terms of mechanics.
Introduction: Runes are an ancient and powerful form of magic originating, according to various scholars and sages, with the Mound People. Others claim that the Dwarves created this form of magic due to apparent similarities to their current written language. Just as many theories point to the ancient and lost empire of the elves and still more point to some strange and horrifying origin from the darkness before the world. The truth is, nobody currently living and willing to speak on the topic knows the origin of this form of magic.
Runes are an ideographic form of magic rather than the phonetic magical languages: i.e., one rune represents an entire word or concept rather than just a sound. One rune carries all the power of the idea behind it. Thus, a rune of Death is more than just the runic word for that concept, but carries with it all the attendant baggage that philosophers have written libraries of books about. They are complicated and difficult to learn and, according to some, impossible to master.
Learning a Rune:In order to learn a rune, a source of information must first be found. Preferably, this will be a person already accomplished in runic magic who can pass on the secrets of that particular ideogram personally, though it is possible to learn from a text or by spending a good deal of time researching an example of a complete rune (such research would most certainly be time consuming and possibly expensive, most certainly hazardous). Even with proper instruction, the learning process is far from certain. The time required to learn a rune is equal to 20 days less the average of the character's WIS and INT. These days must be spent in at least 8 consecutive hours of study. Significant interruption will require the learner to start again. If the character only has a text as his source material, the time is 30 days less the average of WIS and INT. Researching a rune without any assistance is a process goverened entirely by the DM.
At the end of this time period, the character will again take the average of his Intelligence and Wisdom. He must then roll 3d6 with a result equal to or less than his averaged mental attributes to successfully learn the power of that particular rune. Rolling above this number results in failure and the character may not try again to learn this particular rune.
A character of any race or class can attempt to learn a rune, though most frequent users are Humans, Dwarves, Fighters, Druids, and Mages. Clerics tend to eschew runes as they gain their power from a higher, purer source. Elves, on the other hand, have no particular incapability of using runes, but find them abhorent for some unspoken reason and will not willingly make use of them and may even drive away obvious users of runes.
Ok, here's where things get a little hairy in my brain.
Creation and Activation of Runes: To use a rune, a character must carve it. It cannot be written in ink upon a page, traced in the air or sand, or spoken as if it were a simple spell. This magic is deeper and older than such ephemeral cantrips. No, a rune must be carved into at least a semi-permanent medium such as stone, wood, metal, or other similar objects. It is not unheard of for some barbaric cultures to carve runes upon their own flesh. The carving process requires a successful Wisdom check.* A failure indicates an error has been made during the carving.
The activation of a rune requires blood: at least 4hp worth. A character on their own can easily open a sufficient wound in his own body, or the body of a willing volunteer. The blood of an unwilling "volunteer" must be obtained in the usual manner. The blood is smeared over the rune, upon which its power activates and remains active for a short time per the description of the individual runes. A character may activate more than one rune at a time, but doing so requires that he succeed at a Constitution check at -1 for each rune after the first. Thus, activating two runes requires a CON check at -1 while three runes requires a check at CON-2. This check applies even if the blood used to activate the runes is not that of the activating character.
Iron Will Not Bite: This rune is most often used by warriors and those in combat. Upon activation, it will reduce all damage done to the character by iron or steel weapons by 1 point per die. This includes magical weapons, but not any weapon made of stone or wood or without a significant steel component. Typically, such a rune is carved upon armor, a helm, or a pendant. This is the most rune most commonly carved upon flesh in such instances. It cannot be carved upon a weapon or other object, but must be placed upon an item that will enclose, encircle, or otherwise indicate the object or individual to be so protected. Duration is a number of rounds equal to the number of hp worth of blood used to activate it (minimum 4).
Death Oracle: Use of this rune permits the user to contact the spirits of the dead and gain truthful answers to his questions. Activation requires a minimum of 4 hp worth of blood and an additional 1 hp for every 5 years the creature has been dead. Thus, a creature dead only a few days is easy to contact while someone dead for centuries may be impossible to contact without the sacrifice of several living beings. Persons contacted by these means will communicate in their own language and will be compelled to speak truthfully, though nothing prevents them from twisting or misrepresenting facts as long as what they say is factually correct. This rune will remain active for approximately 10 minutes.
I'm not at all happy with the last half of this. It seems . . . cobbled together and half-assed, but such is the way of things when trying to move beyond Vancian casting at times.
*I had thought about throwing in a proficiency called "runecraft" or some such thing, but then I realized that only about 1% of the gaming world would continue reading past the mention of such a thing. So . . .