True Spell Casting: True 20

True Spellcasting – an Alternate Spellcasting Rule for True20

I have been enjoying playing with True20 off and on and it has really met my needs in a game, but there are still some things about it that I miss from other games. In particular is magic.

The True20 powers system is a very good one and it can emulate almost any magical system I have wanted to try, but there is one area where it falls short and that is in terms of spells. By spells I mean magical effects that are typically written down and can be learned or taught. Yes, very similar to D&D, but also spells that could be found in Call of Cthulhu or the Buffy the Vampire Slayer RPGs.

Why Spells?
Part of it is one of storytelling, sometimes I need a one-time magical effect and I don’t really need a new power to describe it or I need a way of transmitting the knowledge of magical effects in a portable means; ie. in books.
The other the is one of necessity. I have dozens of D&D 3.x/d20 books, many are filled with spells, so all in all hundreds if not thousands of spells.
Wouldn’t powers-as-spells work just as well? Well yes, and in fact it would work for I guess 80% or more of all the spells. With a limited power selection the difference between Adepts are often mostly cosmetic.
Also there are spells that there are not True20 Power equivalents, wish is a good example, and most of the spells in d20 Call of Cthulhu.
And finally, I like to run a magic-rich game. True20 is perfect for this low-magic game I am working on now, but less so to emulate say D&D or my modern horror/supernatural game.

How to Do it?
I do not want to abandon the Power structure in True20, nor do I want to adopt the d20 Spell system wholesale either, but a simple compromise seems to work out well.

To do this I have created a new Supernatural Power called simply enough, Spellcasting. An adept can take Spellcasting up to nine (9) times.
To actually cast the spell the adept uses the Spellcasting power just like any other power.

Spellcasting 1
Concentration
You can cast spells of the First Level. Read the spell description for effects and it the spell needs to be Maintained and if it is Fatiguing.

Spellcasting 2
Concentration
Prerequisite: Spellcasting 1
As Spellcasting 1 except now the caster can cast spells of Second Level.

And so on…

Learning Spells
Taking the power at a new level is not enough to cast spells. The adept must first take the power then learn the spell. This allows the Gamemaster to control which spells can be entered into the game. It also allows which spells can or can’t be learned. For example the Gamemaster can restrict Wizard spells or even “Ranger” spells to a particular group of casters, or even by schools or descriptors (Necromancy or “Fire”).
Spells could be learned via enrollment in specialized “Wizard schools” (D&D or Harry Potter), from occult libraries (Buffy) or found in ancient tomes (Army of Darkness, Call of Cthulhu).

To learn a spell requires a difficulty check.

DC = 15 + Spell Level (in magic rich games) or 20 + Spell Level (in magic rare game)

The bonus for this check is like a skill check. A d20 + Bonus
Bonus = Power Level (Adept Level + 3) + Key Ability (Intelligence, Wisdom, Charisma)

Alternately you can make this a true skill check with Knowledge (Supernatural) or even bringing in the Spellcraft skill.

If the spells can be found the Adept can learn 3 + Key Ability number of spells per Spell level in total, though they can have as many spells in their library as they can.

For example, Taryn, a 1st level Charisma-based Adept takes Spellcasting 1 as a power. She has Charisma +2. She can cast 1st level spells and can learn up to 5 total 1st level spells (3 + 2). Even though she has a library full of 2nd level spells from her mother, they cannot be learned until she takes Spellcastng 2.

Casting Spells
To cast a spell the Adept needs to have appropriate level of the Spellcasting Power.

Casting a spell is not quite the same as using a Power. They often do require the movement of hands, saying special words and the use of material components. Because of this anytime a spell is cast, a spellcasting check needs to be made.

Spell Casting DC = 10 + Spell level
Bonus = Adept Level +3 + Key Ability.

So in our example Taryn our 1st level adept casts Color Spray, a 1st level spell.
The DC for her to cast this spell is 11 (10 + 1) this represents her getting her colored sand and saying the words.
Her bonus is +6 (Adept level 1, +3, +2 for Charisma). So she needs to roll a 5 or more on a d20.

To Save Against a Spell
DC = 10 + Key Ability + Spell’s Level

Converting Spells
D20 spells are not written like True20 powers, but there is enough similarity to allow conversion, for the most part the conversions are dealt with in the True20 book.

Healing or Damage that does 1d6 per caster level has a damage bonus of +1 per level of the Adept.
For the odd case where damage is 1d8 or more then use the follow conversions.
1d6 per caster level = +1 per adept level
1d8 per caster level = +1 per adept level then +1
1d10 per caster level = +1 per adept level then +2
1d12 per caster level = +1 per adept level then +3

Damage the effects abilities is dealt with the conversions below
1d3, 1d4 = 1
1d6 = 2
1d8 = 3
1d10 = 4
1d12 = 5

Converting Spells, Part 2: d20 Call of Cthulhu
The spells in the d20 Call of Cthulhu are mostly d20 compatible. What they lack are spell levels and most cause some sort of damage to the caster, usually damage to an ability, but often damage in terms of sanity loss.

For ability damage divide the listed damage by 2.
For HP damage use the conversions above.
For Sanity use the Mental Health track from the True20 Companion. Sanity damage effects the base Sanity Bonus (page 88, T20C).

To convert Sanity damage take the amount the of d6’s rolled as the loss. For example if sanity damage is 3d6 then the damage to the Sanity Bonus is -3. For any die other than a d6 then add +1. So Sanity Damage in d20 CoC that causes 2d8 would be 2+1 or -3.

Spells in d20 Call of Cthulhu are all considering to be 1st level in terms of learning and casting. But do not let that fool you. The CoC spells are all difficult to cast and often dangerous to both friends and enemies alike. The DCs to learn the spells are often given not with the spell itself, but the books in which they are written in (the Necronomicon, Nameless Cults, etc.)

Alternately you can consider CoC spells to be of level 10, thus requiring another level of Spellcasting in order to cast, but that removes the ability of the regular investigator to cast these spells.

Converting Spells, Part 3: BESM d20 Advanced Magic
Spells in BESM d20 Advanced Magic were another attempt to overhaul the magic system. Instead of levels the spells are given in terms of DCs.
To find the level of any spell take the DC divide by 10 and round up.