E6 in PF2

 I plan to use a bunch of jargon in this post.  I may or may not explain it.

So to explain at least what the title means:  PF2 is, of course, Pathfinder Second Edition.  E6 refers to "Epic 6", a variant invented for D&D 3.5.  The exact details of how it's implemented in 3.5 aren't needed here, but the important parts to know if you haven't heard of it before is that in E6, once you hit level 6, you stop gaining levels.  Instead, every (some number) of XP, you gain a new feat.

Since everything is a feat in PF2, it seemed to me like it might be interesting to implement this idea in PF2 and see what happened.  These mechanics have not been tested and are probably not totally complete, but people were talking about PF2 on twitter and it made me think I should post these up.

First, the core:

E6 Core Rules

-Once you reach level 6, you cannot gain any further levels.
-Every (X) XP after reaching level 6, you can choose a new feat.  You can select any feat that you qualify for, in any category.  The exact number of XP should be chosen by the GM/group to calibrate the rate of advancement to the desired rate.  Some good defaults are 1,000 XP and 500 XP (so you gain feats at the same rate you would gain levels or double the rate, respectively).
-You cannot gain Master or higher proficiency in any game element that your class does not already have Master proficiency at level 6.  You cannot increase your proficiency rank for your Class DC or weapon specialization effect beyond what it was at level 6, except with the Expert Attacker feat (described later).  You cannot gain a class feature higher than level 6 that increases your proficiency rank with any game element.
-You cannot unlock, learn, or cast a spell of 4th rank or higher.  Any cantrips or focus spells you know never scale beyond 3rd rank.  You cannot increase your level for Spellcasting past 6.

That's the core set of rules; with just those, you can get the basic E6 experience.  But to make it better, we have more to add.  You might notice that the core rules reference that you can't gain a class feature higher than level 6 that improves your proficiency; if you stick with the core rules, there's no point in mentioning that, you can't gain new class features.  But if we add new feats, that suddenly becomes an option.  And we have some new feats to add that will help let characters choose to increase some tricks or balance out a few things that might come out odd at 6th level.  It's also worth thinking about whether you want to use the optional rule for Proficiency Without Level (Archives of Nethys can auto-calculate this for monsters so you don't have to subtract it out yourself).  If you do use PWL, you unlock a significant amount of content for yourself, making a lot more monsters usable.  If you don't, it contributes to a dangerous world where there exist monsters that the PCs simply cannot fight in a meaningful way; a level 6 PC against a level 15 dragon, no matter how many extra feats the level 6 character has, is not going to go well.  The sheer weight of numbers that the dragon has will crush the PC.  (Even with PWL, the dragon's higher proficiency will give it an advantage that might be insurmountable, but it'll be less impossible.)  It's up to you which of these options you prefer.  And now, feats to use with E6.

New feat - Expert Attacker

Prerequisite:  You are level 6, have at least 5 additional feats, and have no way to apply Expert or higher proficiency to an attack roll.

Choose a weapon, spell type, or other method of attack that you are Trained in.  You become Expert in that attack form.  If you choose a spell type, you also become Expert for save DCs.

New feat - Hardiness

You gain hit points as if you had gained a level in your class.

Special:  You can take this feat multiple times.  Its effects stack  Each time you take this feat, increase its rarity by one step (Common, Uncommon, Rare, etc).

New feat - Increased Spell Capacity

You can cast one additional 1st-rank spell per day.

Special:  You can take this feat multiple times.  Each time you take it, increase the rank of the extra spell you can cast until you gain a spell of your highest available rank, then reset it to 1st level next time.  For example, a 6th level sorcerer can cast spells of 1st, 2nd, or 3rd rank.  The first time they take this feat, they can cast an additional 1st-rank spell.  The second time, 2nd-rank; the third time, 3rd-rank.  The fourth time they take this feat, they get another 1st-rank spell.

New feat - Increased Focus Capacity

Prerequisite:  Increased Spell Capacity x3

You gain an additional focus point.  Your maximum number of focus points increases to four.

Special:  You can take this feat multiple times.  Your maximum number of focus points stays four, but if you took the feat and still didn't have four points, you can keep taking it until you get up to four.  (You would probably rather learn more focus spells but it's an option if you want to.)

New feat - Advanced Learning

Increase your effective class level by two for the purpose of qualifying for class feats, class features, and ancestry feats.  You do not actually gain any features or feats when you take this feat.  You cannot gain a banned feature or ability through this.  You do not gain hit points, spell slots, increase your proficiency bonus, or any other effect of gaining levels.   If you take a class feat or class feature higher than 6th level, it may need to be scaled down as described below.

Special:  You can take this feat multiple times.  If your effective class level is 10 or higher, this feat is Uncommon.  If your effective class level is 14 or higher, this feat is Rare.  If your effective class level is 18, this feat is Unique.

New feat - Advanced Class Feature

You gain one class feature above 6th level that your effective level qualifies for through the Advanced Class Learning feat.  This feature cannot contain any banned elements and may need to be scaled down as described below.

Special:  You can take this feat multiple times.

Scaling Down Items and Feats

Many items have cool powers but are too high level; they can easily be scaled down.  If the item deals damage, its damage should be reduced to around 6d6 damage (21 average) (and lower if it has utility effects, large AoE, etc).  If it gives an item bonus to something, the bonus should be no more than +1.  If it has a save DC, the DC should be around 20.  If it has an attack bonus, the bonus should be around +10.  If the item is scaled down to a level below 6, these numbers of course should be even lower.  Use the tables for creating items with magic item bonuses, DC by level, etc, in GM Core.  (Remember an attack bonus is just a DC - 10).  If an element would give resistance, it should be no more than 5 if permanent, 10 if temporary, and halved if it is a particularly broad resistance.

The same is true of higher-level features or feats that may be unlocked.  In many cases the GM's discretion will be required to decide what the exact effect available from a higher level feat or feature will be, or if it's available at a choice at all if it cannot be scaled down to an appropriate level of power while retaining the essential effect.  Some feats or class features may simply deal flat damage and can be scaled down, while others provide significant non-numerical power such as teleportation or flight that are inappropriate and can't be easily scaled down.