Planecasting is a particular kind of magic. It uses formulas, which are spell-like abilities with an accompanying cost in planar points. Formulas are cast with an effective spellcaster level equal to the planecaster level of the relevant class, taken individually for each class. The description of each formula is described in a standard format. This format follows the same pattern as the format of a spell, with the differences described in the spoiler below.
Level and School [Descriptor]
Beneath the formula's name is a line giving the level, school, and descriptor (if any) of the formula. A planecaster cannot learn a formula if it's level is higher than his maximum level of formulas known (taken individually for each class). Planecasting relies on the same schools of magic as spellcasting, but most formulas are from the Conjuration, Evocation or Transmutation schools. Formulas are treated as being spell-like abilities from the relevant school and with the relevant descriptors.
The next line of a formula's description gives the minimum cost (in terms of planar points) required to cast the formula. Because different planecasting classes use different types of planar points, refer to the description of the class on planar points cost.
If the formula fails, the cost is wasted.
Given that formulas are spell-like abilities, they have no component. Therefore, this line is absent.
This is the time it takes to cast the formula. If this line is missing, then the formula has a casting time of 1 standard action.
Some formulas may be further enhanced by spending more planar point than their minimum cost. These formulas are identified with the mention Augmentation: Yes. In this case, see the formula's description for the details. Formulas with the mention Augmentation: No cannot be augmented. Modifying a formula with a metaformula feat is different from an augmentation.
If an augmented formula fails, the augmentation cost is wasted.
Many formulas have the same effect as the spell (or spells) stated in their description. In this case, use the formula's description (with the accompanying level, school, minimum cost, casting time, range, target, etc.) instead of the spell's, but use the spell's for the effect's purpose. If a formula duplicates a spell, it does not count as that spell for the purpose of counterspelling, unless otherwise stated (formulas can however be counterspelled by the same formula).
Planecasting, prestige classes, and prerequisites
Planecasters are different from most other types of spellcasters. As such, they qualify for certain prestige classes and other effects differently.
Levels in a planecasting class qualify a character for prestige classes with the following entry requirements.
* A caster level requirement, if no type (arcane or divine) is specified.
* Ability to cast spells of X level, if no type (arcane or divine) is specified.
* Ability to cast formulas of X level.
* Ability to cast a spell with a specific descriptor, if the planecaster can cast a formula with at least one application with that descriptor.
* Ability to cast a specific spell, if that spell is duplicated by a formula of the same school that the planecaster knows, or by an application of that formula.
Planar points (general information)
Planar points are the ressources on which planecasting is built. Depending of the class, the character may have access to any number of planar points ranging from three to nine, or even more if the character is multiclassed. Planar points represent the amount of planar energy currently at the disposition of the planecaster ; they are still in their plane of origin, but the planecaster drains them in one clean shot to create a temporary convergence of the planes, the result of which is called a formula. As planecasters gain level, they can maintain a greater amount of planar points, gain control over new planes, et cetera.
All planar points follow the same basic mechanic ; the character recovers 1 planar point of each type per minute until he attains his maximum (this "standard" recovery functions even in an Anti-magic Field, but formulas and most ways to quicken the process won't work there). Planar Devotees play by slightly different rules in that they have access to nine types of planar points, but are only attuned to three ; this means the other six are capped at 0 until the character "spins the wheel" and changes his attunement ; refer to the class for more details. Keep track of planar points like you would spell slots, except they are recovered with time and a single casting can require many types of planar points. Except in extremely specific circumstances, a character recovers all his planar points in 10 minutes at most ; enough to be at his maximum for the next encounter.
All types of planar points, along with the plane they are associated with, are given in the list in the spoiler below. Note that dream points, Material points and Far Realm points are not used by any of the current three base classes, but may be used as part of a prestige class or something.
A: air points (Elemental Plane of Air)
Ab: Abyss points (Infinite Layers of the Abyss)
Ar: Arborea points (Olympian Glades of Arborea)
Ast: astral points (Astral Plane)
C: Celestia points (Seven Mounting Heavens of Celestia)
D: dream points (Plane of Dream)
E: earth points (Elemental Plane of Earth)
Ely: Elysium points (Blessed Fields of Elysium)
Eth: ethereal points (Ethereal Plane)
F: fire points (Elemental Plane of Fire)
Far: Far Realm points (Far Realm)
G: Hades points (Gray Wastes of Hades)
H: Hell points (Nine Hells of Baator)
L: Limbo points (Ever-Changing Chaos of Limbo)
M: Material points (Material Plane)
Mech: Mechanus points (Clockwork Nirvana of Mechanus)
N: negative energy points (Negative Energy Plane)
Out: Outland points (Concordant Domain of the Outlands)
P: positive energy points (Positive Energy Plane)
S: shadow points (Plane of Shadow)
W: water points (Elemental Plane of Water)
Many formulas (and applications of formulas) require more than one type of planar points to cast. Why does this happen? There are many possible reasons for this.
The simplest one is because the formula requires planar energy that physically combine into the desired effect ; for example, a Planar Mage who casts Sandstorm creates sand and wind ; it does not, for example, create some sort of paraelemental matter made of air and earth.
Other formulas operate in a sort of alchemical reaction ; for example, black sand (and by extension, the Field of Black Sand application of the Field of Earth formula) is actually made of earth, negative energy, and shadowstuff (energy from the Plane of Shadow).
Finally, some formulas that require multiple sorts of planar points actually draw energy from a plane located between the planes associated with the types of planar points used. Thus, a formula that requires Hell points and Mechanus points may actually harness the power of Acheron, which is located between Hell and Mechanus. Since there are no Acheron points, a Planar Devotee must use less direct (and less cost-efficient) means of affecting that plane, and that requires the use of two other planes adjacent to it.
Some planecasters have discovered formulas that require use of unusual planar combinations. This is the cause of heated debates for scholars as they don't agree as to whether these blendings of planar energy are physical, alchemical or actually the proof of the existence of yet unknown planes. Planeshaping feats are the results of these discoveries ; see the section Quasi-Para-Elemental Planes? below for more details in the specific case of the Planar Mage.
At some point in the history of the inner planes, many of the paraelemental and quasielemental planes were too dangerous for any traveller from these planes to return and tell what they see. While scholars know by now that there exists at least 16 inner planes, evidence suggest that there are more. The problem is, they can't agree on what these planes actually are.
An heated debate ensued between scholars, with many of them writing essays on what they think are these planes, sometimes with the pretention that they have actually seen the place. These works are desperately contradictory, even though those of Kristias Fireflight (an aasimar cleric and mage), Lhitrabel (a pit fiend truenamer) and the Frozen Necromancer (a lich who mastered uttercold) have attained some renown.
It doesn't help that all three of them are wrong, or rather, their discoveries are radically uncomplete. When the paraelemental planes were first discovered a long time ago, a similar controversy ensued, since many of the elements have more than one possible combination. For example, air and water do not always lead to ice, but can also become airy water, coldfire, or rain. However, the four paraelemental planes are actually named in reference to the purest combinations of their component elements. For example, while both ice and rain are made of air and water, ice is the purest of the two (rain has some positive energy in it in the form of lightning).
A closer approximation of the truth (though very few, even amongst planewalkers, know it) is that there are no quasi-para-elemental planes. Rather, there are a certain number of demiplanes that exist between the quasielemental planes themselves, and between them and the paraelemental planes. These demiplanes are called border planes and have properties that combine those of the planes they connect. Due to the multidimensional nature of the inner planes, anyone in a paraelemental plane who travels closer to the Negative Energy Plane or Positive Energy Plane ends up in a border plane ; either one of those that connect two quasielemental planes, or one of those that connect a quasielemental plane and the paraelemental plane he is on currently.
Notes and explanation:
Of course, there are officially no paraelemental or quasielemental plane in 3rd edition, even though the splatbooks were inconsistent about it. Since pretending that there are is simpler and leads to more possible options for the Planar Mage, though, I assume that GMs who will allow the class in their game will also allow these planes.
For quite some time I thought there were no direct mention of quasi-para-elemental planes in canon, unless one consider the three paraelemental planes unique to Dark Sun or the fluff text of the feat Lord of the Uttercold to be proof of the contrary. However, after some online research, it turned out that I was wrong ; a planescape book for AD&D titled The Inner Planes described border regions between the quasielemental planes, and between these planes and the paraelemental planes. These border regions had names of their own, but no collective name. Coming up with the term "border plane" and stating that they are a sub-kind of demiplane was pretty easy, though.
Since I've seen a few homebrewed quasi-para-elemental planes (under another name, of course), I had to come up with an explanation for a GM to "replace" these planes with the border planes (assuming he wants to). My suggestion is that scholars of the material planes do not know the truth because these planes are too deadly to be studied carefully and determine their true nature, at least for now. The name Kristias Fireflight was ripped from one of those homebrews (with which you may or may not be familiar), with the other characters being there to give some depth to it all (and foreshadow possible future homebrews).
Planecasting and reserve feats
Normally, spell-like abilities do not allow the use of reserve feats, but I'm on my way to making an option that let planecasters use them. This is a work in progress.
All three planecasting classes have one thing in common : their list of formulas include a full line of Conjuration (Summoning) formulas. All of these formulas have their own list of summonable creatures and a lot of creatures on these lists cannot be summoned by spells. The actual reason for this is because there simply aren't enough monsters in the books (let alone on the Summon Monster lists) to allow a comfortable selection of monsters from all planes at all level.
Thus, I decided to add monsters that aren't in WotC-published books to the lists of these formulas. The abbreviations in the spoiler below are the ones I use to refer to the sources of theses monsters.
ToA: Terrors of Athas
From EN World's Creature Catalogue:
DIP: Denizens of the Inner Planes
DTP: Denizens of the Transitive Planes
ENWo: In the Creature Catalogue, but not in a pdf
From the Sword & Sorcery line:
RDD: Ravenloft – Denizens of Dread
ToHI: The Tome of Horrors
ToHII: The Tome of Horrors II