I question how "epic" it will feel for your 20th level Fighter (or rogue, or cleric, or sorcerer) to gain a level and learn to cast Magic Missile (for one missile, of course).
I don't think multiclassing is the answer.
Not 20th.... 12th or 18th.
Anyway, what are other options that can be done with class levels, if we deliberately exclude extending 20-level classes? How about prestige classes? The upcoming Paths of Prestige book may help in this area.
IMO it would take a lot of work add 20 or 40 or more levels to a core/base class, given that unlike D&D3.5, Pathfinder likes to have every class level bestow some kind of new meaningful ability or an enhancement of an existing one to the character. It would seem contrived and a cop-out to simply extend 21st levels and beyond with more spell slots, more bonus feats, more sneak attack dice, more rage power slots, and so on. Not to mention the fact that class balance will skew more and more as single-classed spellcasters outpace the single-classed vanilla fighters and vanilla rogues.
But...just for fun, here is a 60-level fighter expansion.
Fighter
Some take up arms for glory, wealth, or revenge. Others do battle to prove themselves, to protect others, or because they know nothing else. Still others learn the ways of weaponcraft to hone their bodies in battle and prove their mettle in the forge of war. Lords of the battlefield, fighters are a disparate lot, training with many weapons or just one, perfecting the uses of armor, learning the fighting techniques of exotic masters, and studying the art of combat, all to shape themselves into living weapons. Far more than mere thugs, these skilled warriors reveal the true deadliness of their weapons, turning hunks of metal into arms capable of taming kingdoms, slaughtering monsters, and rousing the hearts of armies. Soldiers, knights, hunters, and artists of war, fighters are unparalleled champions, and woe to those who dare stand against them.
Role: Fighters excel at combat—defeating their enemies, controlling the flow of battle, and surviving such sorties themselves. While their specific weapons and methods grant them a wide variety of tactics, few can match fighters for sheer battle prowess.
Alignment: Any.
Hit Die: d10.
Class Skills
The fighter's class skills are Climb (Str), Craft (Int), Handle Animal (Cha), Intimidate (Cha), Knowledge (dungeoneering) (Int), Knowledge (engineering) (Int), Profession (Wis), Ride (Dex), Survival (Wis), and Swim (Str).
Skill Ranks per Level: 2 + Int modifier.
Table: Fighter
Code:
Level Base Attack Bonus Fort Ref Will Special
1st +1 +2 +0 +0 Bonus feat
2nd +2 +3 +0 +0 Bonus feat, bravery +1
3rd +3 +3 +1 +1 Armor training 1
4th +4 +4 +1 +1 Bonus feat
5th +5 +4 +1 +1 Weapon training 1
6th +6 / +1 +5 +2 +2 Bonus feat, bravery +2
7th +7 / +2 +5 +2 +2 Armor training 2
8th +8 / +3 +6 +2 +2 Bonus feat
9th +9 / +4 +6 +3 +3 Weapon training 2
10th +10 / +5 +7 +3 +3 Bonus feat, bravery +3
11th +11 / +6 / +1 +7 +3 +3 Armor training 3
12th +12 / +7 / +2 +8 +4 +4 Bonus feat
13th +13 / +8 / +3 +8 +4 +4 Weapon training 3
14th +14 / +9 / +4 +9 +4 +4 Bonus feat, bravery +4
15th +15 / +10 / +5 +9 +5 +5 Armor training 4
16th +16 / +11 / +6 / +1 +10 +5 +5 Bonus feat
17th +17 / +12 / +7 / +2 +10 +5 +5 Weapon training 4
18th +18 / +13 / +8 / +3 +11 +6 +6 Bonus feat, bravery +5
19th +19 / +14 / +9 / +4 +11 +6 +6 Armor mastery 5/—
20th +20 / +15 / +10 / +5 +12 +6 +6 Bonus feat, weapon mastery 1
21st +21 / +16 / +11 / +6 +12 +7 +7 Weapon training 5
22nd +22 / +17 / +12 / +7 +13 +7 +7 Bonus feat, bravery +6
23rd +23 / +18 / +13 / +8 +13 +7 +7 Combat maneuver mastery 1
24th +24 / +19 / +14 / +9 +14 +8 +8 Bonus feat, shield mastery (light)
25th +25 / +20 / +15 / +10 +14 +8 +8 Weapon training 6
26th +26 / +21 / +16 / +11 +15 +8 +8 Bonus feat, bravery +7
27th +27 / +22 / +17 / +12 +15 +9 +9 Armor mastery 6/—
28th +28 / +23 / +18 / +13 +16 +9 +9 Bonus feat, weapon mastery 2
29th +29 / +24 / +19 / +14 +16 +9 +9 Weapon training 7
30th +30 / +25 / +20 / +15 +17 +10 +10 Bonus feat, bravery +8
31st +31 / +26 / +21 / +16 +17 +10 +10 Combat maneuver mastery 2
32nd +32 / +27 / +22 / +17 +18 +10 +10 Bonus feat
33rd +33 / +28 / +23 / +18 +18 +11 +11 Weapon training 8
34th +34 / +29 / +24 / +19 +19 +11 +11 Bonus feat, bravery +9
35th +35 / +30 / +25 / +20 +19 +11 +11 Armor mastery 7/—
36th +36 / +31 / +26 / +21 +20 +12 +12 Bonus feat, weapon mastery 3
37th +37 / +32 / +27 / +22 +20 +12 +12 Weapon training 10
38th +38 / +33 / +28 / +23 +21 +12 +12 Bonus feat, bravery +10
39th +39 / +34 / +29 / +24 +21 +13 +13 Combat maneuver mastery 3
40th +40 / +35 / +30 / +25 +22 +13 +13 Bonus feat, shield mastery (heavy)
41st +41 / +36 / +31 / +26 +22 +13 +13 Weapon training 11
42nd +42 / +37 / +32 / +27 +23 +14 +14 Bonus feat, bravery +11
43rd +43 / +38 / +33 / +28 +23 +14 +14 Armor mastery 8/—
44th +44 / +39 / +34 / +29 +24 +14 +14 Bonus feat, weapon mastery 4
45th +45 / +40 / +35 / +30 +24 +15 +15 Weapon training 12
46th +46 / +41 / +36 / +31 +25 +15 +15 Bonus feat, bravery +12
47th +47 / +42 / +37 / +32 +25 +15 +15 Combat maneuver mastery 4
48th +48 / +43 / +38 / +33 +26 +16 +16 Bonus feat
49th +49 / +44 / +39 / +34 +26 +16 +16 Weapon training 13
50th +50 / +45 / +40 / +35 +27 +16 +16 Bonus feat, bravery +13
51st +51 / +46 / +41 / +36 +27 +17 +17 Armor mastery 9/—
52nd +52 / +47 / +42 / +37 +28 +17 +17 Bonus feat, weapon mastery 5
53rd +53 / +48 / +43 / +38 +28 +17 +17 Weapon training 14
54th +54 / +49 / +44 / +39 +29 +18 +18 Bonus feat, bravery +14
55th +55 / +50 / +45 / +40 +29 +18 +18 Combat maneuver mastery 5
56th +56 / +51 / +46 / +41 +30 +18 +18 Bonus feat, shield mastery (tower)
57th +57 / +52 / +47 / +42 +30 +19 +19 Weapon training 15
58th +58 / +53 / +48 / +43 +31 +19 +19 Bonus feat, bravery +15
59th +59 / +54 / +49 / +44 +31 +19 +19 Armor mastery 10/—
60th +60 / +55 / +50 / +45 +32 +20 +20 Bonus feat, greater weapon mastery
Class Features
The following are class features of the fighter.
Weapon and Armor Proficiency: A fighter is proficient with all simple and martial weapons and with all armor (heavy, light, and medium) and shields (including tower shields).
Bonus Feats: At 1st level, and at every even level thereafter, a fighter gains a bonus feat in addition to those gained from normal advancement (meaning that the fighter gains a feat at every level). These bonus feats must be selected from those listed as combat feats, sometimes also called “fighter bonus feats.”
Upon reaching 4th level, and every four levels thereafter (8th, 12th, and so on), a fighter can choose to learn a new bonus feat in place of a bonus feat he has already learned. In effect, the fighter loses the bonus feat in exchange for the new one. The old feat cannot be one that was used as a prerequisite for another feat, prestige class, or other ability. A fighter can only change one feat at any given level and must choose whether or not to swap the feat at the time he gains a new bonus feat for the level.
Bravery (Ex): Starting at 2nd level, a fighter gains a +1 bonus on Will saves against fear. This bonus increases by +1 for every four levels beyond 2nd.
Armor Training (Ex): Starting at 3rd level, a fighter learns to be more maneuverable while wearing armor. Whenever he is wearing armor, he reduces the armor check penalty by 1 (to a minimum of 0) and increases the maximum Dexterity bonus allowed by his armor by 1. Every four levels thereafter (7th, 11th, 15th, and so on), these bonuses increase by +1 each time, to a maximum –4 reduction of the armor check penalty and a +4 increase of the maximum Dexterity bonus allowed.
In addition, a fighter can also move at his normal speed while wearing medium armor. At 7th level, a fighter can move at his normal speed while wearing heavy armor.
Weapon Training (Ex): Starting at 5th level, a fighter can select one group of weapons, as noted below. Whenever he attacks with a weapon from this group, he gains a +1 bonus on attack and damage rolls.
Every four levels thereafter (9th, 13th, and 17th), a fighter becomes further trained in another group of weapons. He gains a +1 bonus on attack and damage rolls when using a weapon from this group. In addition, the bonuses granted by previous weapon groups increase by +1 each (up to a maximum of +5). For example, when a fighter reaches 9th level, he receives a +1 bonus on attack and damage rolls with one weapon group and a +2 bonus on attack and damage rolls with the weapon group selected at 5th level. Bonuses granted from overlapping groups do not stack. Take the highest bonus granted for a weapon if it resides in two or more groups.
A fighter also adds this bonus to any combat maneuver checks made with weapons from this group. This bonus also applies to the fighter's Combat Maneuver Defense when defending against disarm and sunder attempts made against weapons from this group.
Weapon groups are defined as follows (GMs may add other weapons to these groups, or add entirely new groups):
Axes: bardiche, battleaxe, dwarven waraxe, greataxe, handaxe, heavy pick, hooked axe, knuckle axe, light pick, mattock, orc double axe, pata, and throwing axe
Blades, Heavy: bastard sword, chakram, double chicken saber, double walking stick katana, elven curve blade, falcata, falchion, greatsword, great terbutje, katana, khopesh, longsword, nine-ring broadsword, nodachi, scimitar, scythe, seven-branched sword, shotel, temple sword, terbutje, and two-bladed sword
Blades, Light: bayonet, butterfly sword, dagger, gladius, kama, kerambit, kukri, pata, quadrens, rapier, short sword, sica, sickle, starknife, swordbreaker dagger, sword cane, and wakizashi
Bows: composite longbow, composite shortbow, longbow, and shortbow
Close: bayonet, brass knuckles, dan bong, emei piercer, fighting fan, gauntlet, heavy shield, iron brush, light shield, madu, mere club, punching dagger, sap, scizore, spiked armor, spiked gauntlet, spiked shield, tekko-kagi, tonfa, unarmed strike, wooden stake, and wushu dart
Crossbows: double crossbow, hand crossbow, heavy crossbow, heavy repeating crossbow, light crossbow, light repeating crossbow, and tube arrow shooter
Double: dire flail, dwarven urgrosh, gnome hooked hammer, orc double axe, quarterstaff, and two-bladed sword
Firearms: all one-handed, two-handed, and siege firearms
Flails: chain spear, dire flail, double chained kama, flail, flying blade, heavy flail, kusarigama, kyoketsu shoge, meteor hammer, morningstar, nine-section whip, nunchaku, sansetsukon, scorpion whip, spiked chain, urumi, and whip
Hammers: aklys, battle aspergillum, club, greatclub, heavy mace, light hammer, light mace, mere club, taiaha, tetsubo, wahaika, and warhammer
Monk: bo staff, brass knuckles, butterfly sword, cestus, dan bong, double chained kama, double chicken saber, emei piercer, fighting fan, jutte, kama, kusarigama, kyoketsu shoge, lungshuan tamo, monk's spade, nine-ring broadsword, nine-section whip, nunchaku, quarterstaff, rope dart, sai, sansetsukon, seven-branched sword, shang gou, shuriken, siangham, tiger fork, tonfa, tri-point double-edged sword, unarmed strike, urumi, wushu dart
Natural: unarmed strike and all natural weapons, such as bite, claw, gore, tail, and wing
Polearms: bardiche, bec de corbin, bill, glaive, glaive-guisarme, guisarme, halberd, hooked lance, lucerne hammer, mancatcher, monk's spade, naginata, nodachi, ranseur, and tiger fork
Spears: amentum, boar spear, javelin, harpoon, lance, longspear, pilum, shortspear, sibat, spear, tiger fork, and trident
Thrown: aklys, amentum, atlatl, blowgun, bolas, boomerang, chakram, club, dagger, dart, halfling sling staff, harpoon, javelin, lasso, kestros, light hammer, net, poisoned sand tube, rope dart, shortspear, shuriken, sling, spear, starknife, throwing axe, throwing shield, trident, and wushu dart
Siege Engines: all siege engines
Armor Mastery (Ex): At 19th level, a fighter gains DR 5/— whenever he is wearing armor or using a shield. Every eight levels thereafter (27th, 35th, 43rd, etc.) this DR increases by 1 point.
Weapon Mastery (Ex): At 20th level, a fighter chooses one weapon, such as the longsword, greataxe, or longbow. Any attacks made with that weapon automatically confirm all critical threats and have their damage multiplier increased by 1 (×2 becomes ×3, for example). In addition, he cannot be disarmed while wielding a weapon of this type. Every eight levels thereafter (28th, 36th, 44th, and so on), the fighter may choose one additional weapon to master.
Combat Maneuver Mastery (Ex): At 23rd level, a fighter chooses a combat maneuver, such as grapple or sunder. He gains a +2 bonus to attack rolls and combat maneuver defense when performing or defending against that type of combat maneuver. Every eight levels thereafter (31st, 39th, 47th, and so on), a fighter becomes further trained in another combat maneuver, gaining a +2 bonus on attack rolls and combat maneuver defense related to that combat maneuver. In addition, the bonuses gained for previous combat maneuvers increase by +2 each (up to a maximum of +10). These bonuses stack with those gained from Weapon Training and combat maneuver-associated feats (such as Improved Grapple or Greater Sunder).
Shield Mastery (Ex): At 24th level, a fighter improves his ability to fight while carrying a shield. He is able to treat a light shield like a buckler for purposes of wielding an off-hand weapon or wielding a weapon two-handed (but may still use the shield to bash with). At 40th level, a fighter carrying a heavy shield is able to hold and use other items (other than weapons) in his shield hand. At 56th level, a fighter carrying a tower shield is able to gain total cover on any two adjacent edges of his space.
Greater Weapon Mastery (Ex): At 60th level, a fighter chooses one weapon with which he has Weapon Mastery. The fighter automatically rolls a 20 to hit with that weapon, in addition to the normal benefits gained by Weapon Mastery.
