Skill Based Magic System

[Ferrix]

I was thinking this evening of how it would be possible to convert the standard D&D magic system into one that is skill based. I mean as to say that casters do not prepare a given number of spells per day but instead when attempting to cast they spell they roll some skill check (I'd assume spellcraft) and have it dependant upon that skill check as to whether the spell goes off or not.

This would require probably a few changes:

1. Spellcraft would be based off the casters related ability score, instead of always Intelligence.

2. This could make magic users inherently more powerful.
Potential limiting factors:
-1- spells deal subdual damage when cast
-2- failed castings deal subdual damage
-3- maximum spell pool level per day of successful spells
-4- same as above but including failed spells
-5- same as either of the above but can overcast at the
cost of potential subdual damage/fatigue/etc.
-6- making magic inherently difficult to cast (i.e. higher
than what would be figured DC's)
-7- failure by more than 10 = some screw up chart

Breakdown of limiting factors

1. 2 pt./spell level, 0th level = 1 pt. of subdual damage
2. same as above
3. Total spell levels a caster would have.
4. same as above
5. Same as 3 or 4, but adding in the ability to overcast with double damage for casting as per #1 and triple for failing a casting as per #2. Fatigued after they exceed their pool by their primary ability modifier.
6. 0th level: DC 10
1st level: DC 15
2nd level: DC 20
3rd level: DC 25
4th level: DC 30
5th level: DC 35
6th level: DC 40
7th level: DC 45
8th level: DC 50
9th level: DC 55
10th level: DC 60 (metamagicked)
11th level: DC 65 (metamagicked)
12th level: DC 70 (metamagicked)

Any ideas that other people have used? I like the idea that magic isn't this resource you have a specific amount allotted to you every day but is something in which you have to skill in controlling.

~Ferrix

 

[Ferrix]

I'm not thinking of the class changes that would have to occur, but I know some would have to come from this change in the magic system.

 

[thullgrim]

I do something like this, for mages its spellcraft, for cleric and paladins Knowledge: (their Faith), ranger and druids its wilderness lore, and bards its a perform. Its a mana-based system with the DC to cast a spell being based on the level of the spell with any modifiers. Mana regens a rather quick rate in my game and failing a spellcasting roll results in having to make a save or suffer Con damage. We have only used the system in 3 sessions so its still in a playtest stage. The most common complaint came was that they did not have enough skill points to support this. That came mostly from the cleric though who had no Int mod. Also they were unhappy with the initial DC's of the spells, saying I had them placed to high. I personally think that having a rough 10-15% chance to fail your highest level spell is not that bad but we worked it a little.

 

[Tonguez]

My setting is low magic and I use a skillbased system for Magic.

However 0 Level spells can be cast by ANYONE succeding at a Knowledge 'Prayer' check DC 20

A Caster on the other hand can cast any spell at all with DC being 15*+ (Spell level x5) eg a Lv 3 spell has a DC of 30 a Lv 9 spell has a DC of 60
*This reduces to 10+(S.lvx5) for Wizards

The High DCs for High Level Spells means that Rituals are required to use them (eg a group of Casters can Aid each other, or they can invest Con (either there own or a that of a 'sacrifice') This con is lost permanently - Fort Save DC = Spell level x 5 to make temporary (thus 'powerful spellcasters are often weak and frail - just like in the Conan Chronicles).

I also use a Spell recovery rate of 1 day per spell level (so it takes 3 days to recover a level 3 spell and 9 days to recover a level 9 spell...

 

[Mike Sullivan]

Instead of having it be based off of an existing skill, why not create an new one -- or, better, a new set. So you'd have "Cast Wizard Spells (Int)," "Cast Cleric Spells (Wis)," and "Cast Sorceror Spells (Cha)."

Give the classes in question one more skill point per level, and make those skills exclusive. That seems to me like it's a more elegant solution, and it preserves the basic use of Spellcraft, Knowledge, or whatever (plus, it removes problems of changing the ability-base of the various skills).

 

[netnomad]

Sovereign Stone's Codex Mysterium has a good based skill system as well. I use that and Wild Spellcraft for fumbles.

-Netnomad

 

[seasong]

Theralis Magic Rules

Skip down to "Spell Casting", and you'll see my rules for this.