A hazy idea for a new OSR magic system

Work hours have been a bit chaotic this month, with frequent evening hours and weekend workdays, so I have not really spend much of the long hours of tinkering with ideas that usually lead to me writing things. But all the overtime hours will get me a lot of shorter workdays after Christmas and there’s not really much to do in a gardening store in January anyway. There’s a lot of ideas floating in my mind that I want to pursue further on lazy afternoons and loudly proclaim my conclusions.

Right now I am occupying my free periods during the day with thinking about adapting my new idea for a magic system to an OSR rules system. Which actually turned out a bit more tricky than I thought.

The main concept is that all characters have an amount of spellpower that is calculated by adding the modifier from Wisdom to the number of levels in the mage class. A 4th level mage with a Wisdom of 16 would have a spellpower of 6 (4+2). Any time a spell is cast or a ritual performed, there is a chance for a missfire based on the character’s current spellpower score. At the end of the casting the spellpower score is reduced by a certain number. Dabblers in magic have a high chance of misfires when performing rituals (which does not require any specific character class) but so do even experienced mages who have already cast several spells that day. I like the concept but don’t have any good idea for how to calculate the chance of failure and how to make a die roll to check for a missfire.

I also think about having three categories of magic. Spells, which take one round to cas; incantations, which take 1 minute to cast; and rituals, which take 1 hour to cast. Only characters of the mage class can learn spells and incantations of limited numbers, but rituals are open to anyone who gets his hands on the instructions. However, I found that I have really very few ideas for traditional spells that would fit with my image of how magic performs in action.

One interesting oddity I noticed a few days ago is that all the effects I wanted my old magic system to do no longer fit with the new system. And a good number of things I deliberately chose to exclude seem highly appropriate for the new system. (Except teleportation, which is still out.) My old approach was highly inspired by Star Wars and Avatar, which spells being extensions of the body and mind. Now I feel much stronger drawn to witchcraft and sorcery that focus on dealing with external supernatural beings. Having just read Hellboy again (a review is one of the things I want to write) probably had a huge impact on that change of mind.

2 thoughts on “A hazy idea for a new OSR magic system

  1. Ars Magisterii

    Perhaps spellpower should be based on wisdom score (not modifier) plus level? This gives you fairly fine-grained control over the relative penalty that various spells inflict, and makes the misfire roll fairly simple: roll a d20, and if the roll exceeds the caster’s spellpower, the spell misfires (either 1 or 20 should always misfire to make casting have at least some risk for experienced casters). This means that an individual of average wisdom and no magical experience has roughly a 1/2 chance of actually succeeding at a ritual, which makes it risky but not suicidal.

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    1. Yora Post author

      Perhaps I could add a spell specific risk factor. Easy spells get a bonus to the misfire check so that experienced sorcerers have to be at the end of their endurance to risk failure, while elaborate rituals have a penalty that makes them dangerous even for the best sorcerers and outright suicidal for dabblers.

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