Ethri is a type of energy found in Universe X. It originates from an entity called Tatsuonga, and can be found throughout the Lathrym (and even in Ersis) in a number of forms. Arkn and half-human hybrids channel it to practice magic, and most sentient beings (including Arkn, Dekn, half-breeds, and even humans) can utilize ethric energy to charge Siy. Both SEEKER and U.M.E.E.C. have developed ethri-based technology.
Due to its supernatural properties and applications, ethri is extremely valuable to both the Arkn and the Dekn; competition for ethri is one of the main causes of the war between the two races.
During the creation of .Mainframe, a rebooted .Reality core was used to create a connection between the base and the universe on top of it. Alongside this, a split in the core was created to allow for the universe to be boxed in. This split core was taken over by Fab'rasi; here, the Hethe expended the last of its power to create Tatsuonga: the wellspring of all Ethric energy.
The energy emanating from Tatsuonga began to flow throughout creation. The humans of Ersis were unaware of this energy, until a tear in the Silulis exposed the population of an Origin Seed to massive amounts of ethric energy; this caused them to start to mutate. After this population was forcibly relocated to the Lathrym by a cataclysm, Fab'rasi activated the dormant ethri in the humans of the Empyrium sub-realm; the mystical energy aided in their mutation, transforming them into Arkn. The Arkn later discovered that they could charge the ethri in their blood and channel it, directly accessing Tatsuonga's power to practice magic. The Dekn, however, lacked this natural ethri, and had to find an ethric charge from an external source if they wished to practice magic.
The Ethric Mind and the origin of ethri are known to mortal beings only from scrolls and books written by Jacques. The Source is inaccessible, with no known entrances, and is believed by some to be a myth.
While ethri itself is a type of energy, it can be be found in liquid, gaseous, and solid form.
Liquid ethri is known as ethric fluid. It carries a slight ethric charge, and can be found flowing in rivers, and sometimes erupting from super volcanoes (such as Mortavrest).
Super-heated ethric fluid produces a gaseous form of ethri called ethric steam. Ethric steam holds almost no charge (as much of its energy has been "burned off"). However, it can be used to power Siy-based technology (as seen in Mistria).
When exposed to the right conditions, Ethric Fluid will leave behind a crystallized residue known as ethric crystal. There are three types of ethric crystals:
- Natural Ethrics - a.k.a. "Naturals". The hardest and rarest of ethric crystals, and the most valuable. Formed underground through heat and extreme pressure, they are naturally charged with ethric energy. Their charge is finite (though long-lasting), and they cannot be recharged. They are often used by Dekn to charge Siy. They are marked by a powerful glow, which gradually dims as the charge is used up.
- Rethycs - Medium-soft, naturally empty crystals which can be charged and re-charged like batteries. They are found both underground and (more rarely) in the aftermath of ethric volcanic eruptions. Often used in U.M.E.E.C. and SEEKER technology, they become brittle and will break after extensive use. They emit a dull glow, which gradually dims as the charge is used up.
- Nullithics - Malleable crystals formed from ethric volcanoes, which cannot hold a charge. Due to their softness and wide range of colors, they are often used for ornamental purposes. They emit a very slight, continuous glow.
Ethric Crystals are extremely valuable to the Arkn and Dekn alike. The Sanguinal'estiere made its fortune through the ethric black market, and in fact established Blood Flags just to help them launder ethric crystals. Naturals and Rethrycs are used as currency throughout the Lathrym (as well as in transactions in Ersis). Ethrics used as currency are typically cut down into a small, pebble-sized crystals (as even a small crystal can hold a long-lasting charge); a singular crystal piece is called an etherl, while multiple coins are known as etherin. Larger ethric crystals, which hold a stronger, longer-lasting charge, are often needed for magic-infused technology (such as ethric firearms); however, these are far rarer and more difficult to obtain.
Under the right conditions, artificial Rethrycs can be produced. However, they hold a less "potent" charge than their natural counterparts.
Arkn have ethric energy contained in their blood (i.e. their blood itself possesses ethric properties). This gives them a direct connection to the Tatsuonga, and allows them to channel its power naturally by charging the flecks of ethri in their blood and marrow. Half-breed Arkn (or Hurn) do not have ethri in their bodies, and must channel ethri raw; because of this, they cannot reach the power of a full-blood Arkn, and cannot channel an aura without the use of Rethryc Crystals. Dekn cannot channel ethri, and so cannot fully tap into the Tatsuonga. However, they can connect with the Tatsuonga mentally, enabling them to draw sigils which can be charged with Rethyc crystals to be activated: a form of magic known as Siy, which the Arkn also practice.