Espers are godlike beings you'll encounter throughout the game, and if they're defeated in combat they'll be forced to serve you... basically the Final Fantasy XII version of another Final Fantasy staple - the summon. Like with Quickenings, their gameplay details won't be covered here, instead let's focus on how they affect License Boards. Espers function similarly to Quickenings in that the particular license for each Esper (gained after defeating them in combat) often has licenses behind them.
You remember those little license islands you see on each License Board? Yeah, most of those are connected to the main part of the License Board via an Esper license, which again won't appear until after you subdue that particular Esper. While some of these island licenses can be acquired by purchasing the same license or an adjacent license on another License Board (for example, the Monk's LP 50 and LP 80 Swiftness island licenses can be reached by purchasing the LP 50 or LP 80 Swiftness licenses on another License Board), for most of these island licenses you'll have to buy the Esper license, and use this "Esper Gate" to reach the juicy licenses beyond.
Since only one character can purchase any one Esper license, however, you'll have to carefully pick which Esper Gates lead to the best licenses for each class. On the plus side, if you purchase an Esper license on one License Board, it'll also be unlocked on any other License Board that character has access to. Many of the licenses behind Esper Gates are quite useful, such as adding high end White Magicks to the Monk and Knight, or giving the Machinist access to some of the best Time Magicks in the game. How these Esper-bound licenses affect some jobs dramatically affects their utility, and hence what sort of class combinations are the most potent. After all, you wouldn't want to mix a Time Battlemage and a Machinist due to redundancy, just as it would be a shame to waste the potential of the Knight or Monk by mixing it with a White Mage.
Something that can influence party builds like that is definitely worth discussing in more detail, which is the purpose of the rest of this section. Below you'll find a list of all the Espers, what licenses they unlock on each License Board, and a brief discussion of the best classes (and class combos) to assign those Espers to.
Note: Many of the Esper assigning recommendations assumes you'll be making use of some obvious power combos, like the Black Mage/Monk, Knight/Bushi, Shikari/Foebreaker and/or Archer/Red Battlemage. If you're going for a more unique party, you may have to make some judgment calls with the information provided below.
The Black Mage doesn't need Hand Bombs 2 nor will the Bushi greatly benefit from the Souleater technick. The Time Battlemage will gain access to the White Magick 4 license, which allows them to cast Cura and Raise... which is fine, but by no means stellar. On the other hand the Shikari will get Shades of Black, which may or may not be useful - if your Shikari is paired with a magick-user class or the character has a high Magick Power, it may prove useful from time to time. Of the possibilities that remain, the Foebreaker, Uhlan and White Mage all get Battle Lore, which is a nice boost for melee characters. The White Mage probably doesn't fall into this category, for obvious reasons, especially since the Esper Gate can be circumvented for the White Mage by pairing it with Knight, Red Battlemage or Uhlan.
This leaves the Uhlan and the Foebreaker, who both get Battle Lore, fine boosts to each class's Attack Power. In addition, since the Uhlan/Time Battlemage and Shikari/Foebreaker combos are so popular, both of those combos stand to benefit with the addition of White Magick 4 and Shades of Black, respectively. All in all, the Shikari/Foebreaker is probably going to be your more dedicated melee attacker by late game, so that's the best choice, if you have that job combo. If not, give Adrammelech to the Uhlan/Time Battlemage.
|Black Mage||Hand Bombs 2|
|Shikari||Shades of Black|
|Time Battlemage||White Magick 4|
|White Mage||Battle Lore, Souleater|
Belias is the first Esper you force into thralldom, and as such it should be little surprise that the licenses behind his Esper Gate are unimpressive. Horology isn't a terribly useful technick, and since most classes have Libra and you only need one character using it at a time, that's not worth the trouble, either. That pretty much leaves the Knight's Potion Lore 1 license.
|Knight||Potion Lore 1|
Chaos benefits many jobs greatly, but the top three choices are clearly the Archer (Magick Lore x5), Knight (Excalipur, HP 10, and Revive), and Monk (White Magick 11 and White Magick 12). Fortunately all the Knight's Esper Gate licenses can be bypassed by simply buying the LP 125 Quickening license, and the power combo of Archer/Red Battlemage will get access to those Magick Power licenses via the Red Battlemage License Board. This safely leaves the Monk as far and away the top choice, as White Magick 11 will give them Holy and Esunaga, and White Magick 12 allows them to cast Protectga and Shellga. It's an essential part of making the Black Mage/Monk a truly broken combo.
|Archer||Magick Lore x5|
|Knight||Excalipur, HP 10 (390 HP), Revive|
|Machinist||HP 9 (350 HP)|
|Monk||White Magick 11 - 12|
|Red Battlemage||Greatswords 3|
|Time Battlemage||HP 7 (270 HP)|
|Uhlan||Black Magick 7 - 8|
|White Mage||Greatswords 2, HP 8 (310 HP)|
Cuchalainn offers the Wither technick to the Uhlan and the Shades of Black technick to the Foebreaker, both of which will help them diversify a bit, while the Machinist gains a Magick Lore and the Knight scores another Battle Lore. It should be noted that the Machinist can score this Magick Lore without an Esper if they're paired with White Mage (one of the better combos for the Machinist). If you want to waste Cuchulainn, the White Mage can find the Libra license behind its Esper Gate, while the Bushi can acquire this Esper to learn Stamp.
The real winners, however, are the Red Battlemage and the Shikari. The former can pick up Cuchulainn to reach the Black Magick 8 - 9 licenses, which will teach them Blizzaga, Firaga, Thundaga and Sleepga. The last of those four might not be much of a catch, but the three elemental magicks are a fundamental evolution of the Red Battlemage's magick arsenal, allowing them to function as a competent late-game offensive magick-user in their own right. Sure, they have Ardor, but the elemental diversity provided (as well as the lower MP costs) of Blizzaga and Thundaga make this a very attractive proposition.
On the other hand, the Shikari will gain White Magick 12, which includes Protectga and Shellga. While the Shikari isn't much of a mage, these buffs don't really require Magick Power to be useful, so it's a fine way to add utility to the job. While having a second buffer can't hurt, the Monk can get the same spells as the Shikari (with the benefit of the Chaos Esper), and this is by and far the best use of that Esper. This being the case, having a third such buffer is of dubious value, as there's a good chance you'll always have a use for either your Black Mage/Monk or White Mage. All things considered, you may be better off assigning Cuchulainn with the Red Battlemage, as having what in many cases functions as a secondary Black Mage may prove more useful than a tertiary Protectga/Shellga caster. Either way, it's hard to go wrong.
|Foebreaker||Shades of Black|
|Red Battlemage||Black Magick 8 - 9|
|Shikari||White Magick 12|
Exodus is a difficult Esper to assign, and when that's the case, it's usually for two reasons: it either doesn't help any single job enough to have a clear winner, or there are multiple great choices. Unfortunately, this is a case of the former, not the latter. At first, two possibilities should stand out - the Red Battlemage gains Heavy Armor 8 - 10 and the Foebreaker has Magick Lore x4. Not only does the Foebreaker not terribly need those Magick Lores, but the Foebreaker/Shikari combo will gain access to them, anyways. Likewise, the common combo of Red Battlemage/Archer can get access to Heavy Armor 10 - 12 via the Shemhazai Esper (on the Archer License Board), and use Heavy Armor 10 to island hop and get Heavy Armors 8 - 9 on the Red Battlemage License Board. If you're using either of those two job combinations, then, you don't need to give them the Exodus Esper.
With thouse out of the way, the next most appealing choices are arguably the HP licenses gained by the Knight (HP 9, 350 HP) and the Bushi (HP 12, 500 HP), and the Battle Lore gained by the Time Battlemage. Since the Time Battlemage will likely be paired up with a melee job (Knight or Uhlan), this is initially promising... save for the fact that the melee class they're paired with will likely allow them to access this license without Exodus. That being the case, the Knight/Bushi is another common combination that could certainly use the HP boost, considering it's likely the premier front-liner in the party. Granted, that combo will already get the HP 9 license (courtesy of the Bushi), but adding 500 HP to the Bushi is... well, the best of the available options.
|Black Mage||Heavy Armor 9|
|Bushi||Magick Lore x2|
|Foebreaker||Magick Lore x4|
|Knight||HP 9 (350 HP)|
|Machinist||Green Magick 1|
|Red Battlemage||Heavy Armor 8 - 10|
|Time Battlemage||Battle Lore|
|White Mage||Battle Lore|
Famfrit has a variety of licenses that benefit numerous classes, but there's one stand-out, and a few interesting other possibilities. The White Mage will gain access to Numerology and Daggers 5, but if paired with a Machinist they can gain these via island-hopping... nor are they terribly useful, in the grand scheme of things. The Archer likewise gains HP 10 - 11 (825 HP), but the Red Battlemage/Archer combo will be able to circumvent the Esper Gate. The Black Mage also stands to gain a bit of HP (HP 5, 6 and 8, 730 HP) from Famfrit, but like with the Archer, the addition of another job (in this case the mighty Monk combo) will render this unnecessary.
Excluding the various Magick Lores and Battle Lores, this leaves you with two realstic choices, the Machinist and the Monk. The Monk gains White Magick 10 (Dispelga and Arise), while the Machinist will be able to purchase Time Magick 8 - 10 (Vanishga, Warp, Reflectga, Slowga, Graviga and Hastega). Arise will, of course, give the Monk the ability to revive and fully heal fallen allies and Dispelga allows them to debuff enemies, fully fleshing out their arsenal of White Magicks. Hastega and Slowga will, on the other hand, all but render the Time Battlemage obsolete for many late-game battles, allowing the White Mage to replace them in most battles and, in effect, becoming the ultimate support caster.
It's hard to argue against either, but if push comes to shove, there are plenty of ways to revive a KO'd character, mitigating the necessity of another character with Arise, and both the Red Battlemage and the White Mage can cast Dispel. On the other hand, if your party consists of a Knight/Time Battlemage, a White Mage/Machinist and a Black Mage/Monk, you might be quite content with only one character possessing high-level Time Magicks. In a party that includes a Uhlan/Time Battlemage, however, you might want to give your Machinist the option to substitute for the Time Battlemage.
|Archer||HP 10 - 11 (825 HP)|
|Black Mage||HP 5 - 6, 8 (730 HP)|
|Machinist||Time Magick 8 - 10|
|Monk||White Magick 10|
|Red Battlemage||Battle Lore x2|
|Time Battlemage||Battle Lore|
|White Mage||Daggers 5, Numerology|
Sometimes, mercifully, it's easy to assign an Esper. Hashmal is just such a case. White the Monk gains access to White Magick 4 (Cura and Raise), there's no real competition between that and the Knight's White Magick 8 - 9 (Confuse, Faith, Bravery and Curaja). In the former case, the Monk gains access to an unnecessary and obsolete healing magick, and Raise, which you can achieve just as well by using a Phoenix Down. The Knight, on the other hand, becomes a tertiary healer and buffer, capable of using Bravery and Faith to boost Attack Power and Magick Power (respectively) and the most potent party-healing spell in the game, Curaja. On a lower tier, the Foebreaker gains another rank of Swiftness and the Time Battlemage earns a rank of Channeling. Reducing a support caster's MP costs don't really compare with the magicks the Knight gets, and smart job combos should ensure the Foebreaker gets all the Swiftness ranks without wasting such a potent Esper.
|Black Mage||Hand-Bombs 4|
|Knight||White Magick 8 - 9|
|Monk||White Magick 4|
Considering that Mateus is one of the early Espers you'll encounter in the story, you really shouldn't expect too much in the way of licenses. The Black Mage can claim Mateus to gain Hand-Bombs 3, the Shikari can grab the Gil Toss technick, the Time Battlemage will benefit from HP 6 (230 HP), while the Uhlan will gain two Magick Lores. The clear winner here, however, is again the Knight, who will be able to access White Magick 6 - 7 (Curaga, Regen, Cleanse and Esuna). Curaga, of course, is a powerful single-target healing magick, while Esuna is indispensible for wiping away negative status effects. All in all, it might not be as good as the magicks that Hashmal gives them, but they're a welcome addition to the Knight's budding White Magick arsenal, especially in light of the alternatives.
|Black Mage||Hand-Bombs 3|
|Knight||White Magick 6 - 7|
|Time Battlemage||HP 6 (230 HP)|
|Uhlan||Magick Lore x2|
Shemhazai's best licenses are behind Esper Gates on the Red Battlemage and Archer boards. Needless to say, if you have a Red Battlemage/Archer combo, this is a no-brainer, as the Red Battlemage will get White Magick 7 (Cleanse and Esuna) and the Archer will be able to access Heavy Armor 10 - 12. Picking up the Heavy Armor 10 license on the Archer License Board will, in turn, allow you to island hop on the Red Battlemage board and grab Heavy Armor 8 - 9, as well, giving the Red Battlemage/Archer access to the most diverse selection of armor in the game. None of the other possibilities even come close, and failing having a Red Battlemage/Archer in your party, the Red Mage's White Magick 7 license (mostly for Esuna) and Heavy Armor 10 - 12 for the Archer (for the welcome Strength boost these armors provide) are fine choices in their own right.
|Archer||Heavy Armor 10 - 12|
|Black Mage||Heavy Armor 7|
|Knight||Potion Lore 2|
|Monk||Potion Lore 3|
|Red Battlemage||White Magick 7|
|Shikari||Guns 5 - 6|
|White Mage||HP 6 (230 HP)|
Ultima was probably a more interesting Esper before The Zodiac Age, as many of its more potent Esper Gate licenses are now somewhat redundant... assuming you picked good class combos, anyways. The Foebreaker will be able to purchase another rank of Swiftness with Ultima, but ideally smart class comboing makes this unnecessary. The Monk also gains two ranks of Swiftness, which can both be obtained without this Esper by pairing the Monk with any job that can access the LP 50 or LP 80 Swiftness licenses (one of the reasons why the Monk/Black Mage combo is so potent). Time Battlemage gets Swords 7 - 8, but if you go with the two more useful combinations - Knight and Uhlan - you won't need these weapons... they're not even the most potent swords, in any event. By process of elimination, then, this leaves the Knight's Battle Lore and Telekinesis licenses as the best left, since the Knight otherwise is fairly limited when it comes to long-ranged options, this is a welcome addition, indeed.
|Knight||Battle Lore, Telekinesis|
|Machinist||Magick Lore x3|
|Red Battlemage||Greatswords 1 - 2|
|Shikari||Potion Lore x2|
|Time Battlemage||Swords 7 - 8|
One of the more disappointing optional Espers, as far as its Esper Gates go, Zalera offers little of serious interest. The Monk and Foebreaker both can pick up this Esper to purchase the Traveler technick, the Black Mage can obtain Steal and Poach and the Time Battlemage gains access to the Ether Lore 3 license. More interestingly, the Bushi can use the Zalera Esper Gate to reach the Bloodsword and Karkata licenses, but by the time you get Zalera much of the benefit of getting a Karkata early has passed you by already, and of course the Bushi/Knight combo doesn't need this. That leaves the Shikari, who will be able to pick up the HP 11 (435 HP) license, a fine HP boost for a decidedly melee-focused class.
|Black Mage||Steal, Poach|
|Shikari||HP 11 (435 HP)|
|Time Battlemage||Ether Lore 3|
Zalera wasn't a strong entry into the Z-category, and Zeromus doesn't really help matters out much. The Time Battlemage gains the Addle and Shear technicks, the Red Battlemage can make use of Zeromus to acquire a rank of Channeling, the Monk can obtain Sight Unseeing and the Black Mage can nab Heavy Armor 9. None of those are terribly interesting. On the other hand, the Bushi can pick up two more Magick Lores, while the Foebreaker can score a whopping four Magick Lores, although if paired with a Shikari, they can get them without Zeromus. This leaves the White Mage, who gains HP 7 (270 HP) and the Machinist, who can use Zermous to reach the Hand-Bombs 3 license. While the HP may be tempting for the White Mage, if you have a White Mage/Machinist, they'll get that HP license from the Machinist class.
All in all, if you have a White Mage/Machinist and a Foebreaker/Shikari, you can safely ignore Zeromus for them. That leaves the two ranks of Magick Lore for the Bushi and the rank of Channeling for the Red Battlemage, both of which are fine choices. While the Bushi could certainly use more Magick Lore (especially if paired with the Knight), if you gave Cuchulainn to the Red Battlemage, you might as well give them Zeromus for their third and final rank of Channeling, making them a more competent mage.
|Black Mage||Heavy Armor 9|
|Bushi||Magick Lore x2|
|Foebreaker||Magick Lore x4|
|Time Battlemage||Addle, Shear|
|White Mage||HP 7 (270 HP)|
The last of the three Z-name Espers, Zodiark certainly has the most interesting licenses. The White Mage, in a rather poor attempt to make a warrior out of a clearly non-warrior job - can use the Zodiark Esper to reach the Greatswords 1 license, a decided waste of this Esper. The Machinist, meanwhile, can obtain HP 10 (390 HP), which may be tempting with the White Mage/Machinist combo. The Red Battlemage can also get the Greatswords 4 license, while their common combo class, the Archer, can acquire the Infuse and 1000 Needles technicks. The Knight has a great selection of licenses, including Revive, HP 10 (390 HP) and Excalipur, but since they can simply buy the 125 LP Quickening Gate to get the same licenses, it's impossible to justify giving them Zodiark. The Time Battlemage tantalizingly gains the Swords 9 license, which they don't need if they're paired with either the Knight or Uhlan, and the Bush gets Heavy Armor 9 - 11, which they also don't need if paired with the Knight.
Last and certainly not least, however, is the Monk, who gains White Magick 13 (Renew) - the ultimate healing magick, which fully heals the entire party... just in case Curaja doesn't cut it. Since the Monk and White Mage are the only two jobs that can access this potent White Magick (and the Monk can only do so with an Esper's help), and the Monk already has access to a variety of White Magicks that make them a competent secondary healer (especially if combined with the Black Mage for the Magick Lores and Mystic Armor), this is a unique opportunity that shouldn't be missed.
|Archer||Infuse, 1000 Needles|
|Bushi||Heavy Armor 9 - 11|
|Knight||Excalipur, HP 10 (390 HP), Revive|
|Machinist||HP 10 (390 HP)|
|Monk||White Magick 13|
|Red Battlemage||Greatswords 4|
|Time Battlemage||Swords 9|
|White Mage||Greatswords 1|