Elixirs

An Elixir, also known as a panacea, is a powerful, quasi-miraculous medicine that is believed by many to have first been created by a kind hearted god of healing, goodness, and alchemy. It is a divine medicine that is as valuable as something like a Philosopher's Stone, which grants eternal youth so long as it is used once per month, but does not cure illnesses. Elixirs can cure any virtually any diseases, even magical ones. Gods can make them, and so can some of the most skilled alchemists in existence.

-The Alchemist's Atlas, an ancient book on wondrous alchemical inventions.

Elixirs are incredibly powerful medicines that can cure virtually any disease. They are a divine medicine that can be produced by skilled gods of creation, healing, and alchemy, as well as incredibly skilled alchemists. 
Elixirs are valuable because other alchemical concoctions are not capable of curing magical diseases as readily as they are. Greater potions could cure comparatively minor magical diseases like Demonic Infection, but truly powerful magical diseases like the reality-warping someone who is infected by an abomination's spit or blood after surviving an attack by such a monster suffers from are harder to cure. It is for those sorts of diseases that elixirs come in quite handy. 

Trivia:

• The only non-divine, non-angelic, alchemist introduced so far with the skills needed to make an elixir by hand would be Milene Ardor, who until relatively recently wouldn't have been interested in making medicines when she could be making poisons. She is among the top five most skilled alchemists in all of Althos' divine realm.
• Attempting to separate portions of an elixir from the rest of the elixir renders the entire potion non-divine and ineffective, a lesson which was learned and then passed down not long after some of the first elixirs were made. 
• An elixir was offered to Irene Taylor, as part of the offer to persuade her to start a cult to demons generally, and to the Hungering Void specifically. She accepted those terms.
• An elixir can cure any condition aside from one directly inflicted on someone by a god of disease. 
• There are kings and queens in the past, and in the present, who've offered titles, lands, and even the hands of their descendants in marriage to anyone with the skill needed to brew an elixir.

Mechanics & Inner Workings

The key to an elixir is the unicorn's blood. Unicorn's blood is natural medicinal, but the other components amplify its effects, supercharging the healing aspect, and not using any other magic on it allows its natural healing properties to become concentrated while it finishes bubbling. A unicorn's blood that was willingly given is much easier to work with since a unicorn is a faerie and fey are innately mystical. 
The reason for the Leprechauns' coin is that those coins absorb impurities and that property is given to the elixir when the coin is dropped into the unicorn's blood. As for the spells on the spell-paper, the spells don't go off, but the blood absorbs the intention of the magic and uses that will and attitude to enhance itself.

Manufacturing process

Alchemy is a weird science, and like other magical sciences, the rules it follows are vague, at best. As a result of that, there is a factor of chance that is involved in the production of elixirs, even for those alchemists who have the skills to reliably, in theory, produce the magical medicines. That said, here is the method by which an elixir is produced:

1. Pour the drops of unicorn blood into the mortar and begin to boil them using your own magical power. Unicorn blood, outside of the unicorn's body, is extremely easy to boil, but if the blood of the unicorn was given willingly it will take next to no magical power to cause the blood to bubble.
2. Once the blood is bubbling it will remain bubbling for an hour without any intervention. This is the time you have to complete the rest of the process. It should not take the full hour.
3. Slice up the apple into five equal parts, or at least as equal as you can slice it up into. Place the five parts equidistant from each other in the mortar.
4. Use the pestle to grind the apples into mush. As you complete the rest of the manufacturing process the bubbling blood will cause the apple mush to vanish and be absorbed by the blood.
5. Place the coin in the mortar. If the coin begins to disappear in the bubbling blood that is a good sign.
6. Grab the spell-paper and place it into the mortar. If the spell paper is destroyed and the elixir turns from silver, or white, that's a sign that your elixir is ready to go.
7. If the elixir is ready, pour it from the mortar and into the glass vial. Arcane vials don't work, for reasons that are unclear to mortal scholars but likely have to do with the divinity of the elixir clashing with the spells on the vial. Once fully poured into a vial the elixir will change colors for the next forty-five minutes while gradually ceasing its bubbling. About an hour after it ceases bubbling it should be the color of molten gold. If it is, congratulations you have an elixir! Elixirs are worth millions of virtually any currency imaginable, so consider how to use your elixir wisely.

Significance

An elixir is an incredible potion of healing that can heal any disease aside from one inflicted personally by a deity of disease. It can remove any negative condition and can otherwise save one's life, healing any wound and even bring back someone dying, provided they haven't died yet. 
There are less than ten kingdoms that have even a single one of them in their borders in the Althonite Empire. They could be considered blessings that are given to a kingdom by a god of healing and alchemy who approves of them and their governing.

Item type

Medical

Rarity

Immensely rare. Less than 100 alchemists in the empire, as of chapter 198, could successfully brew an elixir even if their lives depended on it. Althos can make them easily, even if he did it through alchemy, and Milene, the most skilled alchemist character revealed to date, could make one if she was serious about it.

Weight

8 ounces per standard issue glass vial.

Base Price

1 Vial (which can be drunk twice before any leftover fluid loses its magic) is worth 1,000,000 Althons

Raw materials & Components

Only some of the difficulty involved in brewing an elixir comes from the ingredients, which is saying something about how difficult they are to make. The ingredients are as follows:

1. Five drops of unicorn blood, if they are willingly given that is incredibly helpful.
2. A coin from a leprechaun's pot of gold.
3. A non-magical apple, though ones born from blessed trees are fine. 
4. A single sheet of arcane, spell-paper, inscribed with potent spells of healing. If this comes from the person making the elixir that is the best possible option, even if the brewer of the elixir wouldn't actually have the spiritual energy needed to cast the spells. 
5. A simple glass vial to pour the elixir into. 
6. Springwater to bring to a boil.

Tools

A mortar and pestle, and minor magical ability, for a few steps in the process.