Spell Backfire rules needed

[Seule]

Does anyone have rules for spell backfires, either house rules or published? I'm considering a system where magic isn't so much a science as an art and casting can fail. Anyone have anything like this?

--Seule

 

[Gothmog]

Here are the spellcasting rules I have been using for the last 2 years- they work pretty well so far. Note that I don't use sorcerers in my campaign- so I made up a mechanic for spontaneous casting of spells for both divine and arcane casters. NO balance problems so far, and it keeps magic from being so reliable and boring.

 

[Red Spire Press]

Does anyone have rules for spell backfires, either house rules or published? I'm considering a system where magic isn't so much a science as an art and casting can fail. Anyone have anything like this?

Magic is a science in Dark Legacies (see link in sig), but since when can science never fail? That being said, DL will include a good deal of rules on how to destroy your body and soul by casting spells. Fun for the whole family.

 

[Cheiromancer]

Ronin Arts has published a PDF called "Lost Spells."

You can find it here: http://www.rpgnow.com/product_info.php?products_id=2167&

 

[Plane Sailing]

I have a variant for spell backfires associated with metamagic use.

In essence, metamagic doesn't increase the spell level you prepare it at, but it increases its instability. The base chance of failure is 10% per spell level that would have been added.

Thus attempting to cast a silent magic missile has a 10% failure chance.
Attempting to cast a quickened, maximised magic missile has a 70% failure chance (+4+3 x10).

If a spell fails there is an equal probability of the spell backfiring. If it backfires the result depends upon the spell.

damaging spells ground zero at the caster.
other spells fail in an unusual or entertaining fashion (or do 1d6 per spell level damage to the caster, as per scroll mishaps).

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I didn't include sorcerers in this consideration - if I did I would allow them to cast as a full round action at the normal percentage failure, or as a normal action for double the failure chance

I hope this may be helpful!
Cheers

 

[bensei]

The Umbragia Setting has a mana-based system for arcane casters. One important feature is that a caster can keep on casting spells which drive his mana into the negative. This casting, however, incurres backfire, which are effects depending on spell level and current mana-value.

All can be found in the Book of Arcane Casters, which can be PDF-downloaded for free.

 

[Darmanicus]

Does anyone have rules for spell backfires, either house rules or published? I'm considering a system where magic isn't so much a science as an art and casting can fail. Anyone have anything like this?

--Seule

Check out the book Wild Spellcraft, it has several different methods for spell failure and several tables to determine what happens. I'm using the book myself and have found it to be really good fun to use.