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Matrix Spell Casting

Copyright Tim Dugger ©2002

A d20 System Licensed Product

Fire and Forget is the most common method of describing the magic system used in the D20 System. The concept that a spell caster can automatically cast any spell he has prepared with no chance of failure, or disastrous result to himself or those around him seems completely foreign to me. My own personal belief says that magic is a mysterious and dangerous thing to attempt to control, and while spells are mostly nothing more than codified methods of utilizing this magic, there should still be some element of danger inherent in the use of it. The following rules correct what I believe to be an error on the part of the designers of the D20 System. It brings back that element of danger, and extends what magic users are capable of without making the unbalanced compared with the rest of the game.

What is magic - Magic is made up of several parts. The first being mana, and the next being the spell matrix. A spell caster casts a spell first by creating the matrix, and then by empowering it with mana. A long time ago I wrote an article describing my view on The Ecology of Magic and while it was written for another system, the concepts developed in it are easily converted to this system's framework. I won't go into details about it, but you can read the original article if you like.

    Mana - Mana is a form of psychoactive energy. The source of this energy is unknown, and scholars across the ages have argued about where it comes from, with no final decision ever being reached.

    Spell Matrix- This is a three dimensional lattice-like framework. Once formed, if it is empowered (by pushing mana through it), it can make changes to the very fabric of reality. These changes are as varied as can be, everything from healing damage to creating huge balls of fire to hurl at an enemy.

There are many different ways to form these Spell Matrices. Some casters use a focus, such as a holy symbol, while others use material items that are consumed in the casting, as the core of the matrix formed. A few rare magic users use their own bodies as a focus for these unimaginable energies, just to name a few....

One major point about this set of spell casting rules is that when preparing spells for the day, all magic users are actually preparing (studying, memorizing, praying for, etc..) a set of Spell Matrices. The caster may then use any of his spell slots (number of spells per day) to cast any spell that he has prepared of an equal or lesser level (equal or less than the spell slot that is). Casting a spell also does not remove the matrix, even though it does use up one of the spell slots for the day. Thus a Wizard need only prepare one Magic Missile spell, and can then cast it any number of times per day, so long as he has the spell slots to power it. The same goes for a Druid who wants to cast Magic Fang.

    Note: This system does not change the normal number of spells per day that a spell caster may actually cast. The charts for the number of Spells per Day are used to determine the number of Spell Matrices and Spell Slots that a caster has access to each day. Both are equal to the number of Spells per Day that a caster normally has.

Since this system tends to tread upon one of the unique features of the Sorcerer, the following changes are made to that class to compensate.

  • The Sorcerer no longer needs material components to cast spells. He now uses his own body as a focus for spells that he casts. If a spell requires a high priced material component, the Sorcerer pays this cost in experience points equal to the gold piece value of the component. If a spell requires both an expensive component and an experience point cost, then the Sorcerer pays both costs as experience point costs.
  • The Sorcerer now gains Bonus Spells Known as the other spell using classes. He uses his Charisma score to determine how many additional spells he knows.
  • The Sorcerer gains a natural +2 bonus to all Spellcasting Rolls. This ability does stack with the Innate Spellcaster Feat below.

Spellcasting Roll - Due to the very dangerous nature of magic, spell casting is not always an automatic success. To successfully cast a spell, the caster must roll (1d20 + caster level + spell stat modifier) and beat a DC of (10 + (2 x spell's level)). Success means that the spell is cast successfully. Failure means that the spell slot was used but that the spell was not cast. A Catastrophic Failure (roll of 1 on the d20) means that the spell slot and the matrix were both lost. The magic user can prepare the matrix again the next day. For a Sorcerer, this means that he has lost the ability to select that particular spell for the rest of the day. He will be able to meditate and recover the lost knowledge of the spell come the next day.

Spell users will no longer have to make a separate roll for Arcane Spell Failure due to armor worn. This is now incorporated into the Spellcasting Roll. For each 5% chance of Arcane Spell Failure, the spell user receives a +1 modifier to the DC of spells that he attempts to cast.

Overcasting - A spell user may attempt to cast more spells than normally allowed in a given day, but this comes at a great cost to the spell user. First, his Spellcasting DC is modified by +2 for every spell over his normal number allowed that he attempts to cast. This modifier is cumulative with itself so that the first spell above the normal number allowed is has +2 to the DC, then second has a +4 to the DC, and so forth. Even if the spell is successfully cast, the caster will take a number of points of Temporary Constitution Damage equal to the level of the spell just cast. There is no way to avoid this damage. If the caster should happen to fail his Spellcasting Roll when Overcasting, he takes a number of points of Permanent Constitution Damage equal to the level of the spell just cast, plus the spell is treated as if the caster had rolled a Catastrophic Failure as detailed above. Both the Temporary and Permanent damage may be healed as per the normal methods outlined for restoring ability damage.

It is important to note that caster does not have to be completely out of available spell slots to be able to Overcast a spell. If a mage is out of third level spell slots, but still has first and second level slots available, he may still attempt to cast a third level spell by Overcasting.

Overloading - Overloading a spell is the act of using a higher-level spell slot to power a lower level spell. Overloading a spell raises the effective casting level of a spell (thus raising the DC of the Spellcasting Roll and the DC of the Saving Throw against the spell) by the difference between the normal level of the spell and the spell slot being used (using a third level slot to power a first level spell increases the level of the spell by 2). If the Spellcasting Roll for an Overloaded spell should fail, it is treated as a Catastrophic Failure, as detailed above.

New Feat

    Innate Spellcaster
    Prerequisites: The ability to cast spells
    Benefits: The caster who gains this an innate bonus of +2 to all Spellcasting Rolls.
    Notes: This Feat may be taken only once.


Appendix A

This article: "Matrix Spell Casting", Copyright © 2002 by Tim Dugger, is a d20 System Licensed Product.

'd20 System' and the 'd20 System' logo are Trademarks owned by Wizards of the Coast and are used according to the terms of the d20 System License version 1.0. Copies of this License can be found at and This article is covered by the Open Gaming License. The title "Matrix Spell Casting" is Product Identity, all other material in this article is Open Gaming Content. Portions of this work are derived from the d20 System Reference Document, Copyright © 1999, 2000 by Wizards of the Coast, and are used with permission.

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Open Game License v 1.0 Copyright 2000, Wizards of the Coast, Inc. System Reference Document v1.0 Copyright (C) 1999,2000 Wizards of the Coast, Inc, "Matrix Spell Casting", Copyright © 2002 by Tim Dugger.

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