What methods exist to get infinite or extremely high caster level prior to epic levels?

Question

In a recent answer, KRyan mentions that there are multiple tricks to get infinite caster level in 3.5. I'm not aware of very many, and those I am aware of require iffy rules interpretations:

• Greater Consumptive Field (SpC, p. 51) does not work on its own (even with a permissive reading of the spell, it caps out at twice your unimproved caster level). However, alternating castings of Greater Consumptive Field and Consumptive Field will work if you read "your original caster level" to mean "your caster level before you increase it with this casting" and not "your caster level before any temporary increases."
• The other high-impact caster level trick I'm aware of is combining Ur-Priest (CD, p. 70) with Sublime Chord (CA, p. 60) to exploit their non-standard caster level calculations. This trick was popularized by the early optimization showcase The Wish and The Word. However, I believe this trick requires conflating "caster level" with "levels in spellcasting classes," and therefore doesn't actually work.

What other tricks exist pre-epic to achieve infinite or extremely high caster levels (say, caster level >100 at character level 20)? Which ones require permissive readings of the rules, and which are more airtight?

Answer 1

This one is setting-dependent, but if you're in FR, the Red Wizard prestige class has a feature known as circle casting. If you get 3 or more red wizards together, each of the supporting casters can burn a spell slot to give the primary caster a bonus to their caster level for the day, and the bonus is equal to the spell slot spent, per caster. Edit: KRyan has a good reminder here about the Hathran and the Halruaan elder, although of the three the red wizard probably has the easiest IC justification for forcing others to help depending on the reasons you're looking.

It works RAW but requires some effort and manipulation on your part. However, even if you're the only mage in the party, it's not out of bounds for a red wizard to coerce or even threaten and force other, weaker red wizards to participate in such a circle. At a certain level of red wizard you can get up to 9 supporting casters, which if you make a collection of lesser minions who can cast, we'll say, 5th level spells, puts you at 45+ your caster level.

In a pinch, you might even bribe other red wizards to participate in such a circle. If you can pull it off, the clever move is to arrange a pact of mutual benefit; seek out a smaller circle of red wizards that will each gather and do this mutually for each other (much more challenging but more consistent and less costly) on some kind of regular and predefined condition/terms.

It's an old question, but it's the first one without an accepted answer I felt comfortable answering. Hope it helps.

Answer 2

Sublime Chord:

A sublime chord’s caster level for both her sublime chord spells and the spells she gains from other arcane spellcasting classes is determined by adding her sublime chord level to 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.

Yathrinshee:

Necromancer (Ex): The yathrinshee has unsurpassed power over death. When she casts spells from the school of necromancy, all her spellcaster levels stack for the purpose of determining her effective caster level. She does not gain higher-level spells any faster than normal or gain any additional spells per day, but the spells she casts are much more effective.

Theurgic Specialist feat:

When casting a spell from your specialist school (off the spell list of any spellcasting class you have), you can add together the caster levels of all your spellcasting classes to determine your caster level. For example, a 3rd-level druid/1st-level sorcerer/3rd-level diviner could cast any spell from the divination school as a 7th-level caster (even when casting a druid or sorcerer spell).

Wizard (Necromancy) 3/Sorcerer 1/Savage Bard 1/Ur-Priest 3/Yathrinshee 1/Dread Necromancer 1/Sublime Chord 1/Mystic Theurge (Ur-Priest/Sublime Chord) 9.

9th level Divine (Ur-Priest), 9th level Arcane (Sublime Chord).

Sublime Chord: Choose Wizard (Necromancy) as arcane class.

• Wizard (Necromancy) + Sublime Chord: 3 + 10 = 13
• Sorcerer + Sublime Chord: 1 + 10 = 11
• Savage Bard + Sublime Chord: 1 + 10 = 11
• Dread Necromancer + Sublime Chord: 1 + 10 = 11
• Sublime Chord (+ Wizard): 10 + 3 = 13
• Ur-Priest + Sublime Chord: 10 + 10 = 20

Yahtrinsee (All spellcaster levels stack for Necromancy): 13 + 11 + 11 + 11 + 13 + 20 = 79 effective Caster Level in Necromancy, for EVERY class.

Theurgic Specialist (Add together all spellcaster levels for specialist school): 6 * 79 = 474

Necromancy Caster Level total: 474.

Answer 3

Dunno if you're still interested in an answer to this question, but I've got one, so.

Play an artificer.

Artificers don't, precisely, have spells, they instead have infusions, which is basically "here are spells you can cast in you have an item to slap them on. You can also cast them directly on a construct. But they're not spells. But you have a caster level." They also make magic items, and can basically fake having a relevant spell for crafting with a Use Magic Device check.

That's sort of the fundamentals. Here's how you get infinite/arbitrarily high caster level-

You need a staff (because they will use the wielder's caster level if higher than than their own), and the infusions Skill Enhancement (gives you an uncapped bonus to a skill through "this object what you are holding") and Item Alteration (changes the type of bonus granted by an item, including things that give those bonuses because they're infused), and while it's not necessary, you're going to want to have Power Surge on that staff too (adds temporary charges to a charged magic item based on caster level).

And then you just sit there and twiddle your staff for a bit until you're satisfied with your Use Magic Device modifier, and then you can run around using UMD to activate staffs of whatever by using UMD to pretend you have the necessary caster level and spell knowledge to use the staff.