EDIT: You may find a revised version of this guide in the spoiler block at the very bottom of the post. I gave up when I realized that attempting to write a guide describing the most slavishly literal RAW was futile - the designers were never 100% consistent, so the system doesn't just get overpowered, it fails to be coherent entirely. Thus, this version of the guide will remain until I get bored enough to update it and port it over to the new boards.

Also, I realized how Consumptive Field works. I'm a seriously lazy dude, so I'm not going to add it in below, but essentially you nearly double your CL, with rounding errors. Because the stacking rules prohibit the spell from stacking with other castings ("Same Effect More than Once in Different Strengths"), each casting's maximum CL boost increases by 1/2 the previous casting's (with the initial casting working just as normal). This resolves to a series of +1/2, +3/4, +7/8, +15/16, rounding down, until rounding error brings the bonus down to +0 over the previous casting. Because it's a spell effect, it applies after all the rules below - so you can just about double all the numbers below.

And now the guide

---------------------------

One of the most preposterously overpowered tricks in the game is to take advantage of poorly worded class features, spells, and feats to boost your caster level to levels never intended by the designers. Many of these tricks work, but some of them don't work the way you think. This guide is your outline to the most common methods of jacking your CL into the stratosphere with feedback loops, and how these loops interact with each other. This is not a guide for practical optimization. Most of these will result in characters too powerful to play outside of PvP with similar characters.

I need tips on organizing this guide, so for now it's going to be more of a haphazard list. But let's get started anyway.

Mystic Fire Paladin is quite nice, since it will let you set your Paladin CL as equal to your caster level in anything else, +2. Since Master Spellthief only applies to your arcane spells, it doesn't help for crazy stacking, but you can still achieve nice results. Since this doesn't make your paladin casting Arcane, it also can't stack with any of the other methods for combining CLs mentioned here. Because of this, it doesn't get included below.

Oh, and the Phaerimm race is stupidly good. If you can talk your DM into letting you play it, you get 9th level spells no matter what you do, and an extra casting progression equal to your character level. This inflates your maximum CL dramatically, as you can seriously take the Knight of the Weave plus Circle Magic plus Master Spellthief route with maximum numbers of casting classes. You end with CL 1602 in this case.

Master Spellthief

Master Spellthief
Prerequisite: Ability to cast 2nd-level arcane spells, steal spell.
Benefit: Your spellthief levels stack with levels of other arcane spellcaster classes (that is, levels of any class that grants arcane spellcasting other than the spellthief) for the purpose of determining what level of spell you can steal. For example, a 4th-level spellthief/4th-level wizard could steal spells of up to 4th level, as if he were an 8th-level spellthief.
Your spellthief and arcane spellcaster levels also stack when determining your caster level for all arcane spells. The character described above would have a caster level of 8th for both his spellthief spells and his wizard spells.
In addition, you do not incur a chance of arcane spell failure for arcane spells cast or stolen from other classes, but only if you are wearing light armor. You incur the normal arcane spell failure chance when wearing medium or heavy armor or when using a shield.

Emphasis is mine. This is the important part. What does it mean? You can add together your spellthief levels and your "arcane spellcasting levels" to determine your caster level for all arcane spells. How you interpret "arcane spellcasting levels" can lead to some different interpretations of how this feat is to work, but the common interpretation is to simply assume that your caster level in all arcane spellcasting classes other than spellthief get added to your level in spellthief. Depending on your DM, however, this may be interpreted to mean your actual level in other spellcasting classes; this essentially means that this feat cannot be used for any shenanigans, as it sums class levels and thus can never exceed your actual character level. Probably the intended interpretation of the feat.

The underlined statement is very important, however: you only add them for your spells, NOT to determine your caster level IN THAT CLASS. This means it cannot be used to meet prerequisites, and it can interact with other abilities that affect caster level in specific ways. Generally, you have to apply this ability last, because it only comes into effect when you actually cast a spell.

Sublime Chord

her level in another arcane spellcasting class. If she had more than one arcane spellcasting class before becoming a sublime chord, she must choose to which class to add her sublime chord levels for the purpose of determining her sublime chord spellcaster level.

Emphasis mine, again. The wording of this, the relevant portion of a Sublime Chord's Spells per Day ability, tells us precisely how to calculate the caster level for a Sublime Chord. This is an interesting ability, because it is dependent on a single other class's level, but applies to all arcane spellcasting classes. Additionally, it's important to bear in mind that it specifically calls out class level, not caster level.

Knight of the Weave

Your caster level for your knight spells is equal to your knight class level plus any other arcane caster levels you may have.

This one is ok. It's Master Spellthief again, but it only applies to your spells for a single class. But it actually sets your caster level here, which allows some excellent looping. Here, unlike with Sublime Chords, your caster level is dependent on caster levels in other classes, and combines ALL of your caster levels, as opposed to a single one. Unfortunately, it sets only a single caster level.

(Greater) Consumptive Field

Additionally, your effective caster level increases by one per death caused by this spell, to a maximum increase of half your original caster level, improving spell effects that are dependent on caster level. (This increase in effective caster level does not grant you access to more spells, and it does not increase the duration of this spell.)

EDIT: This spoiler is included only for posterity. Use the second paragraph at the beginning of the thread.

[spoiler]This one goes a couple of ways, but there are a couple of take-home points. First of all, it only increases effective caster level. Thus, you cannot cast multiple iterations of this spell, increasing the maximum effect with each use; your original caster level does not change between iterations because your caster level does not. You could argue that it's a spell effect dependent on caster levels which an increased caster level improves, and I'd consider that argument passable if the word "original" weren't used. For the purposes of this guide, we're going to assume that this is how it works, because I don't want to dedicate this guide to arguing about it. This is the first interpretation that comes to mind, but I know somebody has done a superior analysis based on overlapping effects. I'm going to wait to enumerate what Consumptive Field does until I find it.

Second of all, it applies to every caster level you have. This becomes valuable when you do things that let you stack caster levels.[/spoiler]

Circle Magic

This provides a pretty absurd boost, but can't contribute to an infinite loop since it's capped. Nevertheless, being able to boost your CL to 40 is quite nice. This applies to all classes, since it specifies no specific class. The example makes clear that the caster level boost is not discharged, which is just tasty. If you're doing a non-infinite loop, a great way to start is to jack all your classes to 40 and then add them. This ability just exacerbates any other loops, so it might not actually belong here. But it's enough of a boost to be included, in my opinion.

COMBOS

This is where shit starts getting silly. Now that we've outlined what each ability actually does, we can get to the crazy awesome bits.

Combining:

Master Spellthief with:
   Sublime Chord: This gets pretty silly. What you do here, is find your highest level arcane spellcasting class BEFORE you took Sublime Chord. It is very important that you, under no circumstances, take a prestige class that provides "+1 level of spellcasting" as its form of casting. These classes don't count toward Sublime Chord, because they're separate class levels from the class they advance, and don't have spellcasting of their own. Once you have a level of Sublime Chord, however, you CAN take such classes and advance Sublime Chord casting, which works just fine since you now gain the benefits of "just as if you'd gained a level of Sublime Chord".
Then you add your level of Sublime Chord to that level. You now have this caster level, as many times as you do arcane spellcasting progressions. Thus, a Bard 1/Wizard 8/Spellthief 1/Sublime Chord 2 has a caster level of 40 (8+2 = 10, 10+10+10+10 = 40) for spells, but only a CL of 10 for anything else CL becomes relevant for (which isn't much). Likewise, a Bard 1/Wizard 3/Master Specialist 4/Sorcerer 1/Spellthief 1/Sublime Chord 1 has a caster level of "only" 20 (3+1 = 4, 4+4+4+4+4 = 20).
   Knight of the Weave: This is less great than it at first appears, but it's still pretty nice. Essentially, every level that isn't Knight of the Weave counts twice; once for determining your Knight of the Weave caster level, and then again for determining your Master Spellthief level. So, a Wizard 18/Spellthief 1/Knight of the Weave 1 has CL 38, which isn't too shabby.
   Consumptive Field:
   Circle Magic: Heh. How many classes of spellcasting do you have? Multiply this number by 40. This is your caster level. Theoretically caps at 800, but if you want to be casting any spells worth your time you'll want 9 levels of Sublime Chord casting at minimum (the further effects of which are detailed below). So, in all likelihood, this is capped at 480.

Sublime Chord with:
   Knight of the Weave: This combination used to cause quite a stir, because some people extrapolated the result to be CL infinity. I'm here to tell you that this is not the case, fortunately. You calculate your Sublime Chord level just as in the Master Spellthief example above, and your Knight of the Weave caster level is set at the sum of that (times however many other classes you have) and your Knight of the Weave levels. Then you swear, loudly and at great length, because Sublime Chord sets it to your caster level in Sublime Chord anyway, just like it does every other class. Alternatively, you have an Undefined Caster Level in Knight of the Weave because it has to be equal, simultaneously, to two separate values. The only way to avoid this is to have Sublime Chord be dependent on Knight of the Weave, but in this case it's dependent on your actual levels in the class and so you suck anyway. Seriously, just don't do this, it saves everyone a great deal of trouble.
   Consumptive Field:
   Circle Magic: All your caster levels get set to 40. Not particularly impressive, but it does mean that you only need enough spell levels to boost your highest CL to 40, as oppose to your lowest (which would be the case if all your caster levels weren't equal). So there's a slight economic savings.

Knight of the Weave with:
   Consumptive Field:
   Circle Magic: All of your caster levels are set to 40, and added to your Knight of the Weave level, which can't be increased further because it's going to be above 40. It is wise, then, to take only a single level of Knight of the Weave; your CL in Knight of the Weave now has a maximum of 761 (19x40+1). Sublime Chord is denied you if you want to exploit this, for reasons discussed above. Unfortunately, that means you'll have to get 9th level spells the hard way, that is by reaching 17th level casting in proper casting classes. This... kinda sucks, actually, because it limits you to a mere 121 CL (17 levels at 40, plus 2 other levels at level 40, plus KotW).

Consumptive Field with:
   Circle Magic:

Master Spellthief AND Sublime Chord with:
   Knight of the Weave: Knight of the Weave counts as just another spellcasting class. Nothing special here, beyond what Master Spellthief and Sublime Chord already bring to the table. If stacking could occur, you'd basically be able to add your highest caster level a number of times equal to the square of how many different progressions you have, which would get pretty insane. CL*Progressions^2.
   Consumptive Field:
   Circle Magic: Works in basically the same way as Master Spellthief plus Circle Magic, with the economic effect granted by Sublime Chord plus Circle Magic. You can nab CL 480 and 9th level spells. Probably the best combination here.

Master Spellthief AND Knight of the Weave with:
   Consumptive Field
   Circle Magic: Absolutely hilarious. All your caster levels get set to 40, summed (for a maximum of 761, as above), to which is added all of your other caster levels (at 40) a second time, essentially sending your CL into the stratosphere at 1521. Unfortunately, you'll only be able to cast shitty spells, so unless you abuse the shit out of Reserves of Strength you can't use it for anything. If you want 9th level spells, you'll have to dump 16 extra levels into pursuing them, leaving you with (at best) CL 241.

Sublime Chord AND Knight of the Weave with:
Actually, I'm not typing this one. We've already established it either breaks the universe or is no different from standard Sublime Chord.

Sublime Chord AND Consumptive Field with:
   Circle Magic:

Knight of the Weave AND Consumptive Field with:
   Circle Magic:

[spoiler]Fuck it. The rules are inconsistent. They switch back and forth between the phrasing "caster level for her spells from X class" and "caster level for X class". We can treat those as identical, which they're clearly intended to be, but then we're in the magical fantasy land of the rules making sense and this whole exercise falls apart because CL shenanigans like this don't make sense. If we don't treat them as identical, then the system breaks because definitions are insufficient to cover all cases.

-Below is the work I'd done up until the above paragraph. I may later pick this up and finish off the equations, but I don't think I'll follow them through to their conclusions, as I strongly suspect the designers' inconsistency has hilariously worked out to balance the game slightly by preventing most of these loops-

Beginning revisions today. The previous guide will remain, spoilered, until I finish.

This guide is your handbook to working out just how to send your caster level spiraling into the stratosphere, using a variety of poorly worded effects. Because this whole thing relies on the literal application of the Rules as Written in flagrant violation of the authors' intent, it's important to be as strict as possible. This means accepting the flaws in the rules that hurt as as well as those that help us. This guide may only be for munchkins, but it's for honest munchkins. There'll be no cheating around here.

I'm going to accompany each of these rules with an equation for what it actually does to the calculation of your caster level. So, the first thing we are going to need is a little bit of notation. For clarity, this guide will always use * for multiplication; thus, CL is a single variable, not C*L.

CL is the variable for Caster Level.
L is the variable for Level in a Spellcasting Class.
ML is the variable for Manifester Level.
TL is the variable for Total Character Level.
A superscript will be used to denote the type of caster level used; ^Arc or ^Div for Arcane or Divine, respectively. A lack of a superscript implies that type is irrelevant.
A subscript will be used to denote which caster level is affected; ₁ represents the highest value of that variable on a given character, while _n represents the lowest. Thus, CL₁ is a character's highest caster level.
A word in brackets accompanying an expression dealing with CL denotes which CL is being calculated; the CL of spells for a given class, or a character's CL for a given class. As established here, these can have different values, and thus we must keep track of it here.

Thus, by default,

[Spells] CL_x = [Character] CL_x = L_x

The caster level of spells for class x is equal to a character's caster level in class x is equal to a character's level in class x.

With that laid out, let us begin breaking the game into itty bitty pieces.

Master Spellthief
[spoiler][spoiler]

Master Spellthief
Prerequisite: Ability to cast 2nd-level arcane spells, steal spell.
Benefit: Your spellthief levels stack with levels of other arcane spellcaster classes (that is, levels of any class that grants arcane spellcasting other than the spellthief) for the purpose of determining what level of spell you can steal. For example, a 4th-level spellthief/4th-level wizard could steal spells of up to 4th level, as if he were an 8th-level spellthief.
Your spellthief and arcane spellcaster levels also stack when determining your caster level for all arcane spells. The character described above would have a caster level of 8th for both his spellthief spells and his wizard spells.
In addition, you do not incur a chance of arcane spell failure for arcane spells cast or stolen from other classes, but only if you are wearing light armor. You incur the normal arcane spell failure chance when wearing medium or heavy armor or when using a shield.

Emphasis is mine.[/spoiler]
Master Spellthief is handy, but it's not as great as it could be. Unfortunately, the wording of "spellthief and arcane spellcaster levels" means that it stacks your actual levels in the class. If it said "spellthief and arcane caster levels", we'd be set. This is a shame, because it means a lot of the really key loops don't actually function. Further, you only use it to set your caster level for your spells, not your caster level in your classes; that means this can't be involved in loops. I cover it here because it's oft-used, and I actually thought it did work the last time I read it.
[/spoiler]

[Spells] CL^Arc_1,...,n = L^Arc_1+...+n

Sublime Chord

her level in another arcane spellcasting class. If she had more than one arcane spellcasting class before becoming a sublime chord, she must choose to which class to add her sublime chord levels for the purpose of determining her sublime chord spellcaster level.

Emphasis mine, again. The wording of this, the relevant portion of a Sublime Chord's Spells per Day ability, tells us precisely how to calculate the caster level for a Sublime Chord. This is an interesting ability, because it is dependent on a single other class's level, but applies to all arcane spellcasting classes. Additionally, it's important to bear in mind that it specifically calls out class level, not caster level.
[/spoiler]

I think I hold the record here. I didn't use circle magic though.

Eh, it incorrectly implements Knight of the Weave. I need to look up Mystic Fire Knight Paladin.

EDIT: Mystic Fire Knight Paladin gets honorable mention. It doesn't make the Paladin casting Arcane, so it doesn't contribute to other summation methods, but it does get to use your pre-Master Spellthief CL.

@Knight of the Weave
You have levels of Sublime Chord, and Knight of the Weave is arcane. Sublime Chord sets your caster level for Knight of the Weave equal to your caster level in Sublime Chord, plus your levels in a single arcane spellcasting class (just like it does all arcane casting classes).

@MFK Paladin
Which ones? Sword of the Arcane Order, at least, doesn't work because Paladins "cast a small number of divine spells" according to their class entry, and Sword of the Arcane Order just lets them prepare wizard spells in those slots; it doesn't say that they're arcane, and since there's already something that says they're divine, it would have to specifically override that.

@MFK Paladin
I don't know.  Me and Kell were working on it and I just trusted him that it worked because he said he had a way.

Sometimes I wouldn't trust Kell as far as I can throw him...He tends to extrapolate TO *a lot* based on whatever 'logic' he thinks he is using.

Quote from: bearsarebrown on November 10, 2010, 01:23:40 AM

@MFK Paladin
I don't know.  Me and Kell were working on it and I just trusted him that it worked because he said he had a way.

Sometimes I wouldn't trust Kell as far as I can throw him...He tends to extrapolate TO *a lot* based on whatever 'logic' he thinks he is using.

Bear in mind most of those tricks involve one of a Dragonblood Pool, Southern Magician, Magical Training, or Alternate Source Spell, and only allow arcane PrC's to progress divine class spellcasting.  You're on your own for funky interactions

That said, this little beast of a handbook is most likely going to reopen my Mind Mage project.  Without using it (or Sublime Chord), I was hitting a CL of well over 100 with ease and with it can most likely hit 4 digits.

Quote

Spellcasting: At each level except 1st, you gain new spells per day and an increase in caster level (and spells known, if applicable) as if you had also gained a level in an arcane spellcasting class to which you belonged before adding the prestige class level. You do not, however, gain any other benefit a character of that class would have gained. If you had more than one arcane spellcasting class before becoming a knight phantom, you must decide to which class to add each level for the purpose of determining spells per day, caster level, and spells known.

This is from the Knight Phantom PrC. Most others are of the same template. The important part is that it adds to your caster level as if you have gained a level in the chosen class. Not just your caster level in that class, or a flat bonus to caster level, but your caster as if you'd gained a level in that class. I would argue that the effects that depend on your levels in arcane spellcasting classes (Master Spellthief, Sublime Chord) should take into account these "virtual spellcaster levels" when determining caster level, spells per day, and spells known (though only CL is actually relevant for this discussion).

Ex: A Bard 7/Full casting PrC 3/Sublime Chord 1 would have a CL of 11 (10 effective Bard levels + 1 SC level) not 8 (7 Bard + 1 SC).



Also, Nar Demonbinder has a caster level boost similar to SC, although it only affects your Demonbinder CL, not your other classes' CLs.

Quote from: http://www.wizards.com/default.asp?x=dnd/ex/20030502a&page=2

Spellcasting: At each demonbinder level, the character gains spells per day according to Table 2-6. He must choose his spells from the Nar demonbinder spell list, below. The demonbinder's caster level is equal to his demonbinder level plus his levels in one other spellcasting class of his choice. To cast a spell, the demonbinder must have a Charisma score of at least 10 + the spell's level. Demonbinder bonus spells are based on Charisma, and saving throws against these spells have a DC of 10 + spell level + the demonbinder's Charisma modifier.

Well, I certainly agree that's the intent. You'll get no argument here. The thing is, though, I'm trying to be as strict as possible in interpreting all of these rules. And Sublime Chord just states that it's based on your "level in another arcane spellcasting class". Which, unfortunately, is pretty clear-cut; it can only look at the levels you actually have, not what your caster level is (which is increased by the PrC as if you had another level) or your spells known/spells per day (which is increased by the PrC as if you had another level). I think it's obvious that the author simply didn't expect people to take more than one PrC; I'm honestly surprised that they even accounted for multiclassing.

Nar Demonbinder is interesting; it's kind of a hybrid of Sublime Chord and Knight of the Weave, although I think it picked just the right aspects of each that it doesn't help matters. Then again, arguably, it applies to all caster levels since it just says "caster level" instead of "caster level for demonbinder spells" or something; opinions? I'm not sure what would be most consistent.

Quote from: Uriel_Ventris on November 10, 2010, 02:12:42 AM

Quote from: bearsarebrown on November 10, 2010, 01:23:40 AM

@MFK Paladin
I don't know.  Me and Kell were working on it and I just trusted him that it worked because he said he had a way.

Sometimes I wouldn't trust Kell as far as I can throw him...He tends to extrapolate TO *a lot* based on whatever 'logic' he thinks he is using.

Bear in mind most of those tricks involve one of a Dragonblood Pool, Southern Magician, Magical Training, or Alternate Source Spell, and only allow arcane PrC's to progress divine class spellcasting.  You're on your own for funky interactions

That said, this little beast of a handbook is most likely going to reopen my Mind Mage project.  Without using it (or Sublime Chord), I was hitting a CL of well over 100 with ease and with it can most likely hit 4 digits.

Oh right, all those monsters. Right, I'll need to expand this thing, I guess (after looking at all those to make sure I think they work) and I should've reserved some posts. Can't help it now, I'll just link the OP to new posts them as I need them. Also, you're to blame for Circle Magic making it in here.

You might want to add in Node Spellcasting with an Acorn of Far Travel.

Seconded, as it's my new favorite toy, and effectively results in NI CL if you have enough time.  By the way, PrC's effectively add spellcaster levels RAW every time they show +1 to existing (arcane/divine/-null-) class.  Otherwise an xyz 10/Sublime Chord 1/Abjurant Champion 5/Sacred Exorcist 4 wouldn't have 9th level spells, and we all know that is absolutely wrong and absurd.  Even looking at only levels for purposes of determining spells, anything that adds to that level is counted.  Not CL mind you, but casting progression.

Psi has very little to offer, but can benefit rather well.

Mind Mage PrC, usually shows up in carnivore's old psion guide, is 8/10 caster+fester class.
Monastic Servant of Auppensser PrC throws one Discipline onto a cleric list, and adds an extra +1CL to the psi side (weird).
Cerebremancer and Mystic Theurge PrCs are well known.
Erudite might get squeezed in due to very good mechanics, but wouldn't be the focus of the build.
Ardent is the kicker on the Psi side, getting "spell" levels via ML not the usual stuff.

Psiotheurgist feat(s) are probably the best bet. Needs the Spell Focus feat for the school/discipline link up.

Otherwise, ANY augment power can utilize a CL based boost.
I'd be willing to bet, a CL+ML combo could reach the point,
of running out of Powerpoints before running out of CL.

I doubt the Psi side has the capability to "explode" this.

Take a max CL build, and gimp it with 2 levels of Ardent
3 feats, and as much dual class advancement as possible.
The psi side does something interesting, but not necessarily something good.
It's more a thought experiment, than anything else.

It's possible that Bloodline 3 / and as many adder classes as possible,
with a hint of Psi, could get an interesting result.
Psi would still be the piggyback, instead of the workhorse.