OSR: Condensed Spellcasting Rules

This post is based on Arnold K's system for GLOG wizards. I've tweaked it, condensed it, and adjusted it for my personal preferences. Your mileage may vary.

Spells are creatures. Angels, demons, spells, enchantments, ghosts, and souls are all more or less the same. Most spells are about as intelligent as a ferret, but they grow and mature just like any living thing. An ancient mage's spells are often as crafty and subtle as their caster, though a spell's mind and goals are still alien.

A wizard's spellbook is a prison or a menagerie. Spells are locked inside, ready to be taken out and loaded into the wizard's brain. A well-trained brain is a mind-gun, loaded each morning with spell-bullets. Minor spells, called cantrips, infest the wizard's soul and bind to it. You can imagine them as extra, mutated limbs, except stuck to the soul and not the body. Spells can be bred and trained.

Wizards train in self-delusion, meditation, and other esoteric techniques to modify their own minds to make them more accommodating to spells, and to tap into the raw magic that suffuses the world. A wizard's mind is a dangerous place. For every 10 students who enter the grand College of Elderstone, only 3 emerge alive and sane.

Wizard Alley, Sean Andrew Murray


It takes 1hr to move any number of spells between your brain and a scroll, spellbook, or wand.

To cast a spell, select a number of Magic Dice (MD) you wish to invest, roll them, and add the numbers together. As a wizard, you get 1 MD per Wizard template. Most spells depend on the number of [dice] invested and the [sum] they show. If you roll doubles, see the Mishap section. If you roll triples, see the Doom section.

Dice that roll 1-3 return to your casting pool and can be used again that day. Dice that roll 4-6 are removed from your casting pool for the day. Your spells return at sunrise to last location they were imprisoned, when the octarine light of the sun touches the world and infuses Creation with an extra boost of raw magic. Your MD return if you get a good night's sleep. If you didn't sleep well, you can Save for each MD to have them return to your pool anyway.


A solid volume, with thick vellum pages and a sturdy cover. Each school produces its own style. Inside, special runes and symbols trap spells inside cages of crystallized thought. Each book contains 10 spell slots. Some spells must be stored across several pages for safety, so the books contain more than 10 pages, and have plenty of room for notes, ledgers, or sketches. Spellbooks start in a waterproof, acid- and fire-resistant bag. Outside the bag, they are not waterproof. They are flammable. And they are also valuable - each book is worth 10gp even if it contains no spells.


A page from a spellbook, effectively, but with some extra magic built in. If you cast a spell from a scroll, you can choose to burn the scroll. If you do, add +1 MD to your roll. This MD does not return to your pool. You can generate Mishaps and Dooms while using a scroll. A blank scroll is worth 1gp.


Wands are like scrolls, but customized for quick use, concealment, and rapid reuse. A wand has a number of banked MD. You can spend these MD when you cast a spell from a wand, but you can't add in your own MD. These MD do not return to your pool (or the wand's pool). It takes the standard 1hr to load a spell from your brain or spellbook into a wand. Using a wand can generate Mishaps and Dooms.

You can choose, when you move a spell, to try to invest 1 MD into the wand. You can only do this once per day, and you take d6 damage from the strain. The MD invested in the wand is permanently added to the wand's MD bank. Each day, you can add another MD to the bank, as above. Banking a MD reduces your total for the day, but you regain the full number of MD with a good night's sleep.

Most wands can only accept 4 banked MD and 1 spell. Larger wands, called staves, can hold up to 6 banked MD and up to 3 spells. Wands are traditionally made from the wood of lightning-struck trees.

Non-spellcasters can use wands. If they suffer a Mishap, use the table from the school that prepared the wand. If they suffer a Doom, the automatically suffer the Third Doom from the wand's school, which usually means instant death.

Identifying Magic

Wizards can smell magic in the air. By tasting, rubbing, or closely inspecting an item, you can tell if it is magic. You may need to test the item to determine what type of magic. You can test Intelligence to see if you can learn anything else about the item without testing it.


If you roll doubles while casting a spell, roll on your school's mishap table. Unless otherwise specified, the spell still works. Magic is dangerous; this was just a hiccough or misfire.


If you roll triples while casting a spell, one of your school's Dooms takes effect. Each school has 3 dooms. The third doom is invariable fatal or worse. All wizards walk a dangerous path. The burn their soul s like candles, and in doing so, court damnation.


  1. Replies
    1. I just condensed everything. There's no substantial mechanical change, except to wands/staves, which are entirely new.

  2. Great stuff!
    Quick question: is a spell cast from the memory "used up" for the day and returns on the next morning (vancian style) or is a wizard able to cast it again as long as he got some MD left?

    1. Spells vanish and return the next day, so no duplicate casting unless you've got 2 copies of the spell.

    2. Thanks for the clarification.
      I'm going to try some one-shots or a small campaign with your GLOG-hack as soon as my current campaigns are finished, and I'm really looking forward to it. :)

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  4. I wouldnt say any of them emerge sane. Just more sane than the rest.