True20's magic system can roughly approximate a wide variety of supernatural genres, especially with inclusion of the ritual magic system presented in the True20 Companion. However, a system of magic where effects are codified into distinct spells -- as seen in Dungeon and Dragons-based worlds, works inspired by D&D or similar products, such as console-based RPGs (Final Fantasy, Dragon Warrior) or the Japanese swords and sorcery genre (Slayers, Record of Lodoss War), and a few other works (Harry Potter being of note) -- is not as well modeled by it. Consider that in D&D, knowing a single spell like Burning Hands gives no ability to either use similar spells (other fire spells, for example) and has only limited ability to be modified. True20 powers on the other hand, are designed to be very broad -- Fire Shaping covers all fire effects, and Elemental Blast covers all 'toss magic at the enemy' effects.
Mostly this was designed so that I could play Slayers using the True20 ruleset. As such I had a number of goals:
The smallest complete unit of magic is the spell. Unlike True20 Powers, spells do one distinct thing (or a few closely related things), and one thing only, though Narrators/other creators of spells may want to group several trivial things together, as in the D&D spell Prestidigitation.
Spells are grouped into schools of related spells. Slayers divides its magic into magic that calls on the gods (white magic), magic that calls on the mazoku (black magic), and magic that calls on the five elements (shamanism). Dungeons and Dragons, 3rd Edition, divides magic into arcane magic, divine magic and psionics, then by school -- evocation, enchantment, conjuration, transmutation, abjuration, necromancy, divination, and illusion -- or discipline in the case of psionics. Schools can provide some insight into how magic is taught in the setting -- for example, healing spells and summoning spells are both conjuration spells, while reviving the dead is distinct from creating the undead in default D&D3e.
Let us call the magic user in this system a Mage, to distinguish it from the Adept role. Plus, someone might decide they want both magic systems in a game, perhaps to simulate different kinds of magic, or a magic/psionic divide, or something. In many respects, a Mage should be identical to an Adept, even sharing Favored Feats.
In this system, a Mage can purchase access to spell schools with feats, just as a True20 Adept could purchase access to Powers. The character then has a Character Level + 3 + Key ability bonus to casting spells from that school. A Mage may also split access into two spell schools at half the normal bonus. This acts analogous to the character's Adept level when casting spells of that school. This determines her casting level check, as well as any saves versus her special abilities and her Fatigue check, which are set to 10 + (Character Level)/2 (minimum of 0) + Key Ability . The Key ability for the spells may be set by the Narrator by school, or the Narrator may leave it up to the players. A Mage gets two spells at each level (with the x4 bonus at first level, just like skill points). Extra spells may be bought via feats.
A multi-role Mage would still have the same bonus as her single-role counterparts, thanks to the Character-Level rule, but she would have fewer spells, and would lack the feats to take many spell schools. As a result, she would either be a specialized full level caster (like a Bard, for example), or a versatile weak caster (a Paladin or Ranger).
Each spell in that school has a set Difficulty in casting it. More difficult spells have a higher Difficulty. As in default True20, one can voluntarily lower one's effective level (to a minimum of 1 point spent) to lower the Fatigue Save.
Example: Joanne's character, Hermione, is a 5th level Mage who has the Spell School Transmutation, and has a Key Ability of +3. This gives her a total bonus to rolls of 11. She wants to cast a spell with a Difficulty of 10. Reasoning that she was well able to make the role, she voluntarily lowers her level to the minimum and Takes 5. She succeeds in casting the spell, and now only has to make a Fatigue Save of 13, as opposed to making a Save of 17. On the other hand, the save of any opponent she was trying to cast a spell on is similarly affected. If Hermione was trying to use the spell to defend herself from a troll, she might want to consider keeping the increased chance of fatigue to raise the chance of it failing its save.
The Adept's Core Ability, The Talent, would also need to be changed for the Mage. While the ability to shed Fatigue with Conviction will be useful for any magic user, The Talent could use tweaking. There are at least two possible options.
Powers to Spells: The Talent could allow one to use spells one doesn't normally know, much as the True20 Talent as written does with Powers. This could represent a D&D-style wizard pulling a rarely-used spell out of his spell book, a D&D-style cleric praying for (and receiving) divine assistance, or any sort of magic user either improvising a spell or remembering some half-forgotten bit of lore from mage school. This would be restricted to spells one actually could cast normally. The upside is that it allows Mages to focus their points on spells they expect to use regularly or in combat, while leaving rarely-used spells to Conviction. The downside is that it makes Mages with Conviction very powerful foes, and difficult to catch off-guard -- not as big as a problem as with Powers, as the Mage wouldn't gain the bonus to use them (if it wasn't from a familiar school) that an Adept does with Powers. Also, given the sheer volume of spells that could exist, it might make playing difficult.
Arcane Expertise: The Talent could also mimic the Expertise ability of Experts -- gaining an additional bonus to rolls in a single school. This could allow for casting some spectacularly powerful spells. On the other hand, this Mage is a lot less versatile than the pervious one, having to either outsource the casting of rarely-used spells or take up more feats.
Personally, I prefer the former, with the note that any player of a Mage should keep a grimoire of spells on hand at the table. (This is also my standard advice for any special abilities – keep it at the table so you don't have to ask the Narrator to look something up.)
It is common in spell-based settings for magic to require or be aided by gestures and words. One should consider the default state of spells in the universe.
Working at a step more than requires gives a -2 Difficulty to the Fatigue save, and any roles to concentrate -- so spending a full round chanting when the default requires a standard action spoken-word would reduce the Difficulty by 2. Working at a step less raises the Difficulty by 2 per step and gives a -2 penalty to cast spells -- casting silently when the default is a full-round chant makes the Fatigue save Difficulty increase by 4 AND puts a -4 penalty to the spell roll itself.
If gestures are required, casting spells without them gives a -2 penalty to cast spells and make Fatigue saves.
d20 assumes that different spellcasters/manifesters' casting abilities do not stack -- so a 2nd level Wizard's caster level is the same as a X+2th level Wizard 2/Cleric X when casting Wizard spells. The default of this system assumes that a Mage is a Mage -- the Narrator may set arcane, divine, and psionic schools/disciplines separately, but the abilities all run off of Mage levels. The end result is similar in feel -- an Mage is either going to be spread thinner (i.e. good at casting, but lacking in all the other feats) by focusing on both (like D&D's Mystic Thurge) or be more specialized (like some of D&D's Necromancer classes available in splat books). If one was inclined to limit such things even more, one could rule that there are separate Arcanist, Divine and Psionic roles, and one's level in each doesn't stack for any ability that depends on one's Mage level. This does weaken someone who works in multiple roles a bit more, since several of his feats would be at reduced effectiveness.
You may cast spells from all schools (just not very well). You may treat schools where you haven't put spell points as having a caster level of 0.
Default: A character may not cast spells from schools without this feat.
Optional Variation: You may cast spells at a caster level of 0 from all schools in a certain discipline, such as arcane magic or psionics. You may take this feat more than once.
You know a single spell unusually well. You may use your full Character Level + 3 + Key Ability, or the bonus for the school the spell is in, whichever is higher, when casting that spell, and that spell alone. This does not confer any special knowledge of other spells in the school. This feat does cover learning the spell.
You gain use of one spell school. You may split this into half access to two spell schools, and use this to either increase one to a full spell school, or learn a new spell school at half normal ability.
A Mage may give up a feat to learn two spells. Unlike feats, spells can not be gained using Conviction, except by using The Talent.
As mentioned above, Dungeons and Dragons has eight schools of magic, as well as a split between Arcane and Divine magic and a set of Psionics similar enough to spells to use mechanics such as levels, but different enough to have six different 'schools' (renamed disciplines). Each is its own spell school, but levels can stack between Mages, as casters who specialize in two of the three (Mystic Theurges, for example) are not unheard of.
The difficulties should be considered a guide. Certain spells may become more or less powerful when used in the True20 System, and goodness knows even in the original system, people can argue for years about whether a spell is placed at the right power level. The Narrator is encouraged to use his discretion when coming up with the Difficulties of spells, or in restricting or banning spells. When a caster can use a spell from multiple schools (aka a spell that is both arcane and divine), she may choose to cast from the school that gives her the highest bonus.
In general, I think the Wizard/Cleric column is scaled best. The other column should only be used for Bard/Ranger/Paladin-only spells, which might be a bit stronger than one would expect for their level.
| Spell Level | Full spell-level classes | Half spell-level classes |
|---|---|---|
| (Wizard, Cleric, Psion) | (Bard, Paladin, Ranger) | |
| 0th | 12 | 12 |
| 1st | 16 | 16 |
| 2nd | 18 | 20 |
| 3rd | 22 | 24 |
| 4th | 24 | 28 |
| 5th | 28 | 32 |
| 6th | 30 | 36 |
| 7th | 34 | -- |
| 8th | 36 | -- |
| 9th | 40 | -- |
To take into account that D&D3e damage needs to scale with hit points, and True20 damage doesn't, note the damage per level, and convert that. For each doubling of the dice rolled (2,4,8,16), add a +3 bonus, as one would do for a Critical Hit. One could also switch this to a +3 bonus for each (full) 5 levels.
Instead of dividing the Divine up into the eight schools, one could divide it up by spheres of influence (Domains) of the caster's god or personal philosophy.
Urban Arcana can be done with the Dungeons and Dragons breakdown above, combined with the Low Magic rules.
The schools for the Slayers magic system are divided into Black Magic, White Magic, and Shamanism (Earth, Air, Fire, Water and Astral Shamanism). Holy Magic also exists, and is related to White Magic, but is not commonly taught, so brings the total to 8 schools.
Characters may start by putting 0 ranks in a number of schools based on their intelligence score (minimum 0). While this gives no bonus besides Key ability to cast spells, just like the Dabbler feat, it does allow characters to cast spells from that school. Spells also may be purchased (via a feat) by any character.
Because of Holy Magic's nature, non-dragons may not purchase it as a 0-rank school, and Dabbler does not cover it, unless said character has a good in-story reason.
Again, this is a rough guide. One could theoretically also use this to bring D&D3e spells and powers into Slayers d20 (or vice versa -- come on, haven't you ever wanted to be able to Dragon Slave something in D&D)?
| Slayers d20 Spell DC | New DC | (D&D Spell Level) |
|---|---|---|
| 20 | 12 | 0th |
| 25 | 16 | 1st |
| 30 | 20 | 2nd-3rd |
| 35 | 24 | 4th |
| 40 | 28 | 5th |
| 45 | 32 | 6th-7th |
| 50 | 36 | 8th |
| 55 | 40 | 9th |
| 60 | 44 | -- |
| 65 | 48 | -- |
| 70 | 52 | -- |