Military: Lossgale Sapphires + Thul ShiftFound in the high mountain peaks by our neighbors, Lossgale Sapphires govern State Changes. Put simply, when they were first struck by a pickaxe they caused a change in the stone they were in, liquefying it without heat being given off, allowing the Sapphire to be extracted..
Modern studies have shown they have a number of uses, with the most common in the Renaissance Era had them used to change the direction of winds and call up a gale from still air. The Thul Shift, a staff studded with Lossgale, could direct the winds to move when swung. And so they were used for wind dances to direct the air around sailing ships for miles around, a Tailwind propelling their Galleons at high speeds to strike at their foes and steal from ships and towns. Moreover, they were also used to completely stall other sailing ships in their sight.
While the age of Sail dawned, all learned to either make treaty with Etroa, or have their ships hunted down to be absorbed into their Empire. However, they were also used to dominate the trade markets economically. Overall, it greatly boosted Etroan Power at the time.
Lossgale Saphires happen to govern States of Matter. Put simply, they are very good at completely ignoring normal laws, turning solid to liquid or gas, or vice versa. While solids don't normally move, Lossgale Saphires can manipulate liquids and gases to cause movement. How this occurs is not truly understood, but the Thul Shift combined the movements of the user in accordance with which way the air was to flow, while seeming to almost read the will of the one who used it. More modern terms would be it receiving the imprint of the creator, and working at the will of the user. In other words, it read the nervous system and brain waves to be programmed to act that way during it's creation. And this is also how it could be directed by a user without any real understanding of physics and sciences.
Lossgale Sapphires look almost a clear blue, and glow with green light when active.
Skytear Sunswords among other weapons made by master blacksmithsOut on the oceans bottom, where tests were being performs for ships made using Sunseeds to power them,(which were failing rather badly), a metal piece fell into the ocean. It sank like a particularly sharp rock before colliding with a boulder. The metal cracked, and sunseeds spilled out before the ended up creating a hot spot.
This admittedly repeated a few times. More ended up in the seashore before the project was abandoned. However, finally the black earth of the seabed began to crack, and what should come up but rocks, rocketing to the surface after having been buried in the earth for millennia.
They came up and up, and entered the sky, before crashing down in our lands. A strange phenomenon, which found that this material become extremely light once it became hot enough, as noticed by the next day the sun ended up starting to lift the things again.
Etroa secured this resource and found more buried on the shorelines. Difficulty to get to, and prone to being blown along with the wind when warm. However, when forged, it's color changed and became extremely light. And once cooled it became hard again, if silvery now.
There was much experimenting with this rock, called Skytears for undoubtedly having fallen from heaven at some point in the distant past. And we created a devastating weapon with it and sunseeds.
Skytears, when used in a folded sword, was extremely heavy. However, by embedding sunseeds into it while it was soft and light during forging, parts of it would be lighter than air. This created a new weapon type that was extremely powerful when swung thanks to it's heavy dense edges, but could be wielded normally thanks to a light center. And the Sunseeds still performed their role in boiling the enemy alive. Moreover, these Skytears would eventually prove to be completely non-magnetic, only being a very strange stone material that could be played with to create masterpieces of weaponry like Maces, Picks, and Buster Swords, among other things.
Military: Rúm & the Protection of EldWe came across a new people and ended up managing to join them to us. The forest country of Eld has long since made use of something they call Rúm, a silver liquid that seeps into objects and changes them. They first used this to guide the trees to grow in certain ways, and to lighten themselves to climb the tall trees away from their foes. Later times saw them apply it to stone and wood weapons to greatly increase their weight and power in combat, and their longbows allowed them great mobility and advantages against their invaders over the years..
However, with the Renaissance, their isolationist times have finally been forced to come to an end by their northern neighbors seeking the wood and animals of the great redwood forest to build their sailing ships. Having come to us, we drove them back with the Rúm made available to us, with more promised, in exchange for leaving their forest be.
Put simply, Rúm can be used to lighten or increase the density of an object, it's weight. Light as air, if not lighter, or heavy as stone and iron, and just as tough.
The main advancement of having Rúm for Etroa as a whole was in metal working. Primarily by adding it to the metals forged in The Angamolen of Damrod during the forging process, metals could be made lightweight, airy, heavy, strong, dense. It greatly boosted the ability to forge strong arms, and the use of Rúm in bullets in particular created a heavy and dense bullet that could pierce most armors of the time.
Later times would eventually come to learn that Rúm was distilled from the sap of the Silver Weirwood Tree which grew in the forests to a height of 30 feet, in comparison to the redwoods which grew far slower and bigger. Their lightness also came to be from applying it to their leather armor and most of their gear, allowing them to hop between the trees upward. No, they didn't tell us how they got it to that level of lightness in leather, we tend to work in metal.Rúm seeps into the structure of objects, and is liquid. It's boiling and freezing points have not been discovered however. Objects can usually only hold a certain amount of Rúm, at which point, it no longer absorbs. Once Rúm has entered something, it doesn't leave. This has lead to a few deaths on it's own due to health problems.
How Rúm is Processed affects the end result of it. Taking the sap and letting it cool over nights would lead to Rúm that makes materials denser. Boiling it over a fire until the water in the pot evaporates creates something that makes an object less dense once absorbed.
Rúm's Sphere happens to be Material Density. That is, manipulating Density of materials. Generally, Denser things either change material form, or require more of that material for the same volume as lighter ones. Though this may not always hold true for all interactions of Rúm.