“Essence” is a complicated word in magical studies. It can mean “the type of esper associated with a certain emotion,” like the “essence of ambition” being choleric esper. It can also refer to the essence of a soul, which means any kind of esper that a human can naturally channel. Of course, since other souls can channel other sorts of esper, some use “essence” to refer to esper, which is pointlessly confusing since we’ve got enough definitions being bandied about and the word esper already exists. For purposes of this section of the text, “essence” is used to refer exclusively to a set of espers found in and spontaneously generated by the human soul (among others) which have certain elements in common with one another, especially the three lumen espers.
These five espers exist on a loose spectrum from light to dark (though all are invisible to the naked eye except when hyper concentrated): Agape, eros, philia, ether, and umbra. The first three are the lumen espers and are quite similar to one another, and it is actually a matter of some debate as to whether eros or philia are brighter than one another. Eros is defined by a softly fluctuating luminescence and mercurial nature, whereas philia is a steady light, dimmer than eros at its brightest and brighter than eros at its dimmest. Agape has the decency to be both steady and extremely bright.
Umbra is the essence of fear. Fear causes it, and when it builds up in a living creature’s soul that creature becomes more fearful. This can potentially cause a feedback loop. Umbra has a tendency to convert other energies into more of itself, but has difficulty doing so unless there is significantly more of it than there is of the other energies. Thus, in most people umbra is not very dangerous, which is good because all known souls produce umbra spontaneously. If umbra builds up too much in a soul, they are corrupted into a shade. Since this large amount of umbra devours new esper as soon as it is created, shades are usually non-sapient, with their ether being devoured almost as fast as it is produced (they also tend to have near identical personalities since their base esper is consumed at a similar rate).
Umbra constantly converts other espers to more umbra, which produces a dearth of those espers, which the soul will continuously attempt to replace only to be again consumed, for so long as the soul remains functioning (which isn’t always very long with the soul burning itself out producing a constant stream of new esper). A shade soul does not have an increased capacity for esper, however, so the umbra is constantly being flung out of the shade for so long as their soul remains functional, giving them an aura of fear. After their soul ceases to function (for most shades, only a few months), the shade collapses into an inert pool of umbra. Shades are instinctively aware that their days are numbered and seek out other souls to devour to feed the fires of their own a little longer, but so much energy is lost in the transfer that a single devoured soul will often give a shade no more than a week’s breathing room.
Powerful wizards whose souls generally produce very large amounts of esper can maintain their sapience after becoming shades by producing ether (and base espers) faster than the umbra reaction can devour them, and some dark wizards choose to do so because shades, immersed in the power of umbra, become immune to its fear-inducing effects, are ageless since their humours (and sometimes entire body) are largely replaced by pure umbra, a shade soul has a huge reserve of esper for casting umbral magic, and the amount of esper they produce means more is converted to umbra means more is thrown out of their soul to make room means their aura of fear is that much more powerful.
The Shadow Realm is an apparently naturally occurring plane of existence fully separate from our own which is strongly infused with umbra. Staying there for extended periods of time turns mortals into shades. The Shadow Realm has been known to devour demesnes (small otherworldly planes of existence usually created and directly ruled by a god, also called demi-planes) whole on occasion, as well as occasionally leech into the mortal world and various other planes of existence. It is hypothesized that if it grows big enough, then just like umbra devouring a soul and turning it into a shade, the Shadow Realm may devour the mortal world and make it a reflection of itself. The rate at which the Shadow Realm devours demi-planes seems to work out to this theory mathematically, though fortunately the Shadow Realm is quite a ways off from being able to devour the mortal world by these calculations as of the writing.
Ether, or spirit esper, is the essence of sapience. Without ether the world can still be perceived but it cannot be understood. Ether otherwise has no impact on the personality, though someone with a melancholic personality is more likely to take the time to analyze a situation, and it is easier to understand something if you spend more time on it. Thus, while melancholic people don’t have more ether, they tend to get more use out of the ether they have (on the other hand, a choleric person would say they spend all their time analyzing and none on putting the understanding to use, and a sanguine or phlegmatic would say that they’re both missing the point of life, to which the melancholic would retort that there isn’t one).
In any case, ether is known as spirit esper because spirits are made almost entirely of it, pure spirit esper filling an otherwise inanimate and mostly incorporeal form. Some spirits are ghosts, the soul of a person with enough concentrated ether in it to remain coherent after being ejected from its no longer functioning body, but the xaos esper root of a soul is rapidly converted to necris esper when not shielded by some kind of corporeal form, and the weight of the necris then drags them down into the land of the dead. Most spirits, and certainly the most stable ones, are spontaneously generated by the vast amount of spirit esper that exists in the Spirit Realm. The Spirit Realm is, like the Shadow Realm with umbra, an alternate plane of existence deeply suffused by ether. Because ether does not react to other esper like umbra does, the Spirit Realm is perfectly safe to visit, however it is impossible for a corporeal being to enter or interact with the Spirit Realm. Instead, the soul must be projected into it.
Ether is an extremely useful substance because it is easily transmuted. This makes it more vulnerable to umbra corruption, which is an ongoing problem in the Spirit Realm which the spirits are constantly vigilant against and, indeed, somewhat hostile towards most mortals (natural sources of this deadly umbra) because of this, giving their respect only to those who are so calm and at peace that they produce only trivially small amounts of umbra (generally speaking, you aren’t likely to get a warm reception in the Spirit Realm unless your soul has less than a tenth of an esper of umbra in it).
In addition to being easily transmuted into umbra, ether can be synthesized with umbra to create infernal esper or with agape to create celestial esper. Ether can also be synthesized with eros, but extremely large amounts of ether is required to trigger the reaction, which results in lycan esper. Finally, it is technically possible to synthesize ether with philia, though the amount of ether required is incredibly large. The result is called mana esper (“mana” means power or prestige in the language of the wizard who discovered it, and the wizard who discovered it used it to summon astral slaves into his harem, which was certainly an emblem of prestige – many peasants in his culture now use the word “mana” interchangeably with “esper,” but since mana is actually the least common of all esper this is extremely incorrect), and though creating even small amounts of mana is extremely difficult, this is, to modern knowledge, the only esper which can open gates to the Astral Realm, so mana does see use in this niche.
Almost any other kind of esper can be transmuted into ether except necris esper through the process of alchemy. Alchemy uses alchemical seals as an ether circuit (sometimes called spirit circuits) to transmute any kind of esper (except necris) into ether, which can then be transmuted into umbra, infernal, celestial, lycan, or mana esper, each of which have their uses.
Alchemy also covers the storage of the various types of esper for large esper spells. Many spells require esper in the high hundreds or low thousands, which is far more than the few hundred that even very skilled wizards generate. Fortunately, the earth element is exceptional at storing various types of esper, its natural petrification energy being well-suited to longterm storage (salt has similar properties with meat). Specially prepared crystals are used to store almost all kinds of esper, with different crystals used for different esper types, but ether is an exception. Ether is stored in metals, and metals with high ether concentrations tend to be rarer, softer, and more valuable. Ether is also an exception in that its transmutative property carries over to the metal it’s stored in. While tenebrous tanzanite, for example, simply cannot contain as much umbra as bloodstone, if you store too much ether in properly prepared lead it will transmute the lead into a more valuable type of metal with only a small amount of ether loss. This trick means that in addition to being used to store ether, you can also use the ether to transmute tin coins to gold and then just spend them. It also means that if you need lots of ether, you can suck it out of gold.
The transmutative properties of ether can also be used to convert raw elements into something useful, and because ether is the stuff of sapience and those elements naturally produce the energies necessary to create a soul, it is possible to use ether to create not only life, but sapient life. Experiments in the creation of homonculi and chimeras have so far been fairly unimpressive compared to naturally occurring life, but the ability to create any kind of functional creature out of nothing but wood, clay, and fire is an accomplishment. A similar process can be used with base espers to create elementals or with umbra to create artificial shades.
The most advanced alchemy uses the transmutative properties of ether to rebalance the esper in the soul, which can heal wounds, calm the mind, and even reverse the effects of aging. The sorcerer’s seal, sometimes called the sorcerer’s stone after a legend regarding a sorcerer who had the seal inscribed upon a stone, is the seal used for this rebalancing, but due to each soul being different the seal must be altered for each person and even from day to day as the balance (or rather, imbalance) of esper in the soul shifts.
Lumen covers three distinct but related forms of esper: Philia, eros, and agape. Each one is generated by a different emotion, but each emotion is similar to the others. Philia is generated by friendship and loyalty. Eros is generated by romantic love and devotion. Agape is generated by general compassion and goodwill for all. It is a common misconception that humans produce an unusually small amount of lumen. While humans generate less lumen than umbra, very few animals can generate lumen, although most of the animals you think of when you think of animals, things like tigers, bears, etc. etc., can generate philia, eros, or sometimes both. Humans are the only animals known to generate agape, and agape generating or channeling creatures are very rare generally. Fortunately for lumen mages, the sun blasts incredible amounts of agape down on a daily basis.
All forms of lumen can be concentrated into a fire which can be used to attack enemies much like real fire, although this is less effective as compared to channeling choleric esper, as lumen is more complicated and requires unbroken focus to channel, unbroken focus being fairly hard to come by in most situations in which you want to light someone on fire. Lumen can also be used to read the emotional state of another. Since lumen reacts differently to the base espers as well as ether or umbra, it is possible to project lumen outwards and then recall it, and this can be used to detect the current esper makeup of another’s soul. With proper training, this can be translated into a current read of their emotions.
Philia is aligned with the stars, which serve as waypoints in both the mortal worlds and in the Astral Realm. The main feature of the Astral Realm is the Ether Sea, sometimes called the Astral Sea, which is a vast ocean of ether. Just like the Spirit Realm, this vast ocean of ether will occasionally generate a spirit made of almost pure ether, but the presence of large amounts of lumen from the countless astral demesnes keeps the ether swirling in currents as it reacts to the lumen, rather than coagulating into psuedo-physical structures as in the Spirit Realm. Thus, astral spirits are usually aquatic creatures adapted to the incorporeal ocean of the Astral Realm.
Those astral demesnes are the stars seen in the sky, and they drift along perfectly predictable paths like clockwork which means, despite the constant motion, they are essentially as stable as landmasses, islands in the Astral Sea with a bizarre topography. The greatest demesnes are ruled over by a god, while others have been claimed by powerful wizards, and still others are taken by mighty spirits of the Astral Sea. While the demesnes are not any more mutable than any place else, the fact that each is a small demi-plane of its own makes them attractive to creatures of such excruciating power that they can reshape local realities to their whim. The relatively small size of a demesne means that the reshaping can be so significant as to alter the fundamental nature of the plane, at which point the plane’s inertia won’t be fighting the reality warping which in turn means that they can be permanently altered to suit the whim of the reshaper. This means that the demesnes are often a reality-bending reflection of the will of whoever controls them. Because of their vast number, many of them are yet unclaimed or their original owners have since died or moved on.
It is often assumed that the natural inhabitants of these demesnes will be friendly since they are principally composed of what is typically seen as a benevolent esper type. This is not so. The inhabitants of the astral demesne are comprised primarily of philia, so while they have a strong tendency towards loyalty even to the point of servitude, this makes many of them if anything more hostile towards outsiders, and many of them (except where reshaped by meddling gods or wizards) have an outright dearth of eros and agape, the two esper types most likely to break down barriers between cultures.
One demesne in particular is a source of some existential panic amongst some wizards. The powerful wizard who controlled this demesne turned it into a replica of the multiverse, with a sky filled with hundreds of stars each the size of a small city rather than a small continent, a mortal realm, and a self-contained Spirit Realm and Shadow Realm. The latter led to an umbra imbalance that led to the actual Shadow Realm devouring it after a few decades, but the fact that such a thing is even possible (and that its ultimate fate could possibly be the ultimate fate of the larger multiverse played out much faster) raises the possibility that our own universe could be some mad wizard’s playground contained within a single demesne in the Astral Sea of some even greater multiverse. On the bright side, this would give us some place to escape to if the umbra does start devouring everything, provided we can find a way out.
Eros is the power of love and is associated with the moon. The moon, also known as the lunar demesne, is close to a quarter the size of the mortal realm and unlike most of the smaller demesnes it is chopped up between multiple powers. Since the lunar demesne is made of eros and not philia, the inhabitants also tend to be very much unhinged and sometimes even dangerous, though it is also a good place to go to be deliriously happy. Eros fluctuates and the lunar demesne fluctuates with it. It is a common misconception (even amongst wizards) that the light of the moon directly fuels the power of lunar magic, but in truth the light of the moon is just an extremely convenient measuring stick. When eros is strong, the moon, which is largely made of eros, will be fully lit. When eros is weak, the moon is dark.
Eros has a strong effect on the mood of those who channel it, making the highs higher and the lows lower. This can extend to the point of insanity if the flow is too strong, a constant danger for wizards channeling eros lumen. Only the strong-willed can retain sanity whilst dealing with this mercurial esper, and even they suffer a significant reduction in mental resilience when eros is feeling unfriendly.
Agape is more powerful than mortals can handle in all but the smallest amounts. Not only that, it is more powerful than creatures comprised of other lumen types can handle. Even eros creatures are uncomfortable when within the Solar Demesne, and philia creatures are actively harmed by the intense amounts of agape there. For mortals, even brief exposure can be and often is lethal. Dark spots of the Solar Demesne, where the agape flows relatively weak, are less fatal, but still often uncomfortable for visitors. As such, despite being over half the size of the mortal realm and flowing with the most powerful esper type known to exist, the population of the Solar Demesne is sparse, mostly limited to gods and their angels.
Being the most powerful esper type known to exist, agape would be quite valuable if it weren’t also all over the place. The only reason wizards don’t use agape exclusively for everything is that it is too powerful. Anyone not well trained in the use of agape is likely to end up with whatever conduit they’re using to channel it fried to a crisp. For anyone not using alchemical conduits of some kind, that conduit is their soul. Even trained users of agape will cause damage to whatever instruments they’re using to try and direct the power (which is again usually their soul), because being more powerful than any other kind of esper, the only thing that can contain agape is the sun, which murders everyone who sets foot on it, which makes it a tad difficult to craft alchemical seals from.