Optional Rules for Fantasy Magic Failure

I voiced my wish to see some chance of spell failure in D&D in my recent post about Fantasy Magic. Having been called out by Bonemaster I have put together my suggestions as to how to use spell failure.

My plan is not to make it a frequent or lethal event, just a way of adding some variety and encouraging some care and thought from wizards. These ideas are based on my theory about the origins of magic.

First, each spell cast requires a “notional” concentration check. This is to ensure the caster does not forget an element of the ritual or fluff it. A roll of 1 denotes a mistake and potential spell failure.

Roll again and add the spell level (bigger spells need more raw magic and hence increase the result of failure). Compare the result to the outcomes below.

0-20 The spell fails and is lost.
21 As above but also lose another random spell (contamination during preparation).
22 Random spell outcome of the same school and level.
23-24 Random spell outcome, opposite school, same level.
25-26 Random spell outcome, same school but random level.
27-28 Random spell outcome of the opposite school but random level.
29 Random target, same spell.
30 Target self, oposite school and random level.

As you can guess, the chance of failure is small and the outcome rarely fatal. Casting level is not an issue as we can all make mistakes. Finally I am assuming the GM will determine the random outcomes. Please give them a try if you are interested or better still, post your ideas and opinions.


  1. I think that losing an addition spell is too likely in your table. What about adding lots of effects that would be great for roleplay, in there, such as the caster’s hat turning into a bunch of butterflies or that he suddenly gains a foot in height? You could maybe even throw the odd beneficial effect in there, such as the spell is lost but is instantly replaced by a random one from his spell book of equal level (who knows how the mechanism for this works – its magic!).

    The Recursion King´s last blog post..Combining miniatures and roleplay

  2. Excellent and many thanks for sharing this.
    I found my way here via viricordova’s (Bard of Valiant) latest posting and have to say you’re making a great universally useful suggestion for spell failures. I think a few suggestions of outcomes could be very helpful especially for younger and less experienced gamemasters, I would love to see something like this on your site.

    looking forward :),

    TheLemming´s last blog post..Google’s Machinae

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