Unique Elements of the Aether

As a plane composed majorly of air - one that suffered an immense magical catastrophe only a couple of millennia ago, at most - the Aether is a place where not all of the expectations of other planes apply.

The Cascade

The Cascade - or, as many of the indigenous peoples of the plane call it, the Shattering - is the cataclysmic event that tore the continents of the Aether into the shards the land now exists as today. Rather than resembling the other planes' single layer of ground with sky above, the Aether used to be a series of overlapping floating continents, each passing through the air independently of the others save for the rare collision. It once housed many advanced civilizations with substantial magical and technological knowledge, and the survivors of these civilizations form the indigenous tribes of the modern Aether.

At a time theorized to be roughly two millenia ago - the start of the modern era, the year 0 ME - a conflict between gods used the Aether as its battleground of choice. The details of the conflict are lost to time, but its end is clear: the collision of the magic of two gods shattered all of the continents of the plan into many smaller islands, fragmenting communities, destroying cities, and leaving pockets of what is now known as aetheryte. This event left only small, scattered groups of survivors who took many years to become the tribes known to the plane today, taking much of the advanced knowledge and culture of these peoples with it.

Scholars theorize that the Cascade left a literal scar in space and time stretching throughout the planes, though the location of this scar within the Aether is unknown.

Colonization

An initial expeditionary force arrived in the Aether approximately 800 years ago (784 ME) as part of an international cooperative effort from the Boundless Sea (Layer 2) to research its bordering planes. Upon discovery of the current state of the Aether and its riches, this expeditionary force was fortified, and soon, massive migration took place from some regions of the plane below. Combined with other smaller migrations from other planes, this formed the basis of the Free Colonies - the unassociated peoples of the Aether not native to this plane. Co-ops became guilds became companies became corporations, and nowadays, the skies unclaimed by a larger power are ruled by coin and steel, with preference given to the former.

Aetheryte and Magical Residuum

The sheer quantity of magical energy emitted by the Cascade twisted and reshaped the literal earth, forming pockets of what is now known as aetheryte. Aetheryte is naturally buoyant in air, keeping many islands afloat, but quickly deteriorates when exposed to water or anti-magic. Aetheryte is an extremely valuable substance as a result, used in the construction of skyships, the creation of artificial islands, and to balance out the import of materials and construction of structures on islands. The methods of creating aetheryte are entirely unknown to the modern world, as is whatever material or property caused continents of the past to float in the sky.

The immense concentration of magic in aetheryte houses a horrifying secret, however: the magical emanations, generally referred to as magical residuum (residuum for short), are hostile to living tissue, causing swift deterioration, life-threatening illness, or horrific mutation to those unlucky enough to be exposed to a sufficient quantity. As a result, aetheryte is handled with protective equipment, often in small quantities and at a distance. Aetheryte can even contaminate the surrounding rock as well, which is why a thin layer of water is often built into the walls of structures that house aetheryte, especially that which sits at the core of a ship or populated island. Residuum is measured in parts-contaminated-per-second (PPS for short), with prolonged exposure to at least 10 PPS sufficient to cause substantial health complications, and momentary exposure to higher quantities able to cause even greater issues. Residuum can also have deleterious effects on magical items, abilities, and enchantments, especially in high concentrations.

Item	Rarity	Cost	Bulk	Description
Residuum Detector	Common	15 gp	L	A simple detector that measures the level of residuum in an area to a single degree of precision, with a maximum measurement of 100 PPS.
High-Grade Residuum Detector	Common	200 gp	1	An advanced detector that measures the level of residuum in an area to the tenth of a unit, with a maximum measurement of 10,000 PPS.

Given the common issue of handling aetheryte and materials saturated with residuum, protective garments are a necessity on ships. Most ships have at least two or three water-suits: suits made up of two layers of water-tight material with water in-between. They don't provide perfect protection, but compared to handling aetheryte without protection, they provide substantial reassurance. Wealthier individuals or those engaged in more dangerous work may choose to wear fancier anti-residuum gear - anything from clothing woven out of many layers of protective material to a heavy, bulky suit that covers nearly the entire body of its wearer - but these are not commonly available and often require special order.

Item	Rarity	Cost	Bulk	Dex Cap	Item Bonus	Description
Water-Suit	Common	20 gp	3 (2)	1	3	A full-body suit woven out of two layers of watertight material containing a thin layer of water. When worn, this armor gives you a +2 Item bonus to Fortitude checks to resist residuum-related effects. In addition, any effect caused by residuum measuring lower than 10 PPS is ignored. If the wearer ever takes piercing or slashing damage, the water-suit is broken and no longer provides this benefit until repaired.
Anti-Residuum Clothing	Uncommon	95 gp	1 (0)	3	1	This bulky but more wearable outfit is crafted from over a dozen layers of varying fabrics with anti-magic properties. When worn, this armor gives you a +2 Item bonus to Fortitude checks to resist residuum-related effects. In addition, any effect caused by residuum measuring lower than 10 PPS is ignored.
Anti-Residuum Suit	Uncommon	600 gp	4 (3)	0	4	This cumbersome suit complete with mirrored visor combines every known defense against residuum, no matter the bulk or cost. When worn, this armor gives you a +4 Item bonus to Fortitude checks to resist residuum-related effects. In addition, any effect caused by residuum measuring lower than 100 PPS is ignored.

At the center of the Aether is the Spire, an immense, ancient construct many miles high, suspended constantly in midair. The Spire is theorized to be the centerpoint, or at least a major point of origin, of the Cascade, and is the largest known source of residuum in the entire plane. As such, it is measurable from nearly any point within range of a specialized residuum detector. When combined with a specially-attuned piece of metal designed to measure the angle from the Spire as well as a magical gauge attuned to hundreds of carefully-placed and monitored ballast buoys to determine height, this tool can be used to accurately determine one's precise location relevant to the Spire.

As traditional magnetic compasses often fail due to the magical concentration of the Aether, an aetheric compass such as the one described above is the primary method of navigation through the plane. Even these have their faults, however: too far from the Spire or too close to large sources of residuum, and all but the best-designed compasses fail. Even those have their failure points, and more than one greedy ship's captain has taken on too large a load of aetheryte only to find themselves drifting until they ran out of supplies, unable to find their bearings.

Item	Rarity	Cost	Bulk	Description
Aetheric Compass	Common	80 gp	3	A residuum detector and spin detector combined with a height gauge, often affixed to a ship's structure due to its size. Measures angle in degrees to two decimal points and residuum in mPPS to two decimal points, up to 10,000 mPPS. May be unreliable near large sources of residuum.

How Not to Fall

If you fall, you'll likely never be heard from again, unless you get lucky enough to fall on an island, a flying creature, or a ship. Enchantments save lives, but are in high demand and are generally only for the wealthy. Many poorer citizens carry makeshift wings to hopefully save their lives in case of emergency, but these are expensive and often single-use. Sturdier, multi-use gliders cost more money, and those carrying enchantments or material strong enough to make further gliding or even flight possible are available but much more expensive.

Item	Rarity	Cost	Bulk	Description
Paper Wings	Common	4 gp	0 (1)	These wings can be activated as a reaction by grabbing onto the thick, folded paper edges and pulling them out like a paper fan to act as aerodynamic webbing. Both hands are used to maintain this activation. As a part of this reaction or as a reaction on a later turn, the wearer may use the Arrest a Fall reaction. When wearing these activated wings, for every ten feet fallen vertically, the wearer may move five feet horizontally. These wings are made of paper and can only survive one fall; once the item is used and the wearer arrives at the ground, the wings are rendered unusable.
Safety Wings	Common	12 gp	1 (2)	These wings can be activated as a reaction by grabbing onto its edges and pulling the wings out to act as aerodynamic webbing. Both hands are used to maintain this activation. As a part of this reaction or as a reaction on a later turn, the wearer may use the Arrest a Fall reaction. When wearing these activated wings, for every ten feet fallen vertically, the wearer may move five feet horizontally. Unlike paper wings, these wings are crafted from treated leathers and skins and are durable enough to survive repeated falls.
Glider	Common	60 gp	1 (2)	This item can be activated as a reaction or as an action. Both hands are used to maintain this activation. When activated, the glider allows its wearer to move 20 feet horizontally for every 5 feet fallen vertically and slows the wearer's fall enough to prevent them from taking damage from the fall, unless they are otherwise knocked out of the air. While wearing this item, the wearer gains access to the Arrest a Fall reaction.
Mechanical Wings	Rare	450 gp*	1 (2)	These hollow wings are crafted from superlight metals reinforced with magical fibers and aetheryte powder and must be integrated into the back of their wielder permanently via a surgery that takes one day of downtime. Once equipped, these wings grant the wearer a permanent 25 foot fly speed, but they'll have to cut holes in the backs of their clothes and armor. These wings are only crafted by one known individual in the world, and she is known to be extremely selective with her clientele and vary her prices accordingly.

Scavenging

With the enormity of the Aether and its cataclysmic past, there's plenty of unclaimed wealth up for the taking. Scavenging is a common pursuit for those without other ties or training looking to improve their standing, though the inherent dangers of such have claimed many lives.

Drifters are what lost ships are called, those who never made it home often due to overly ambitious crews. They're relatively common, and their cargo is often rich as long as you're careful not to end up like them. A drifter can even be repurposed as a ship if it's not too contaminated, though many sailors have superstition about such things.

More common than drifters, however, are islands, often dotted with ruins of things unknown. Many of these, especially further from civilization, have been unexplored for centuries or longer, often holding precious materials, ancient enchantments, or even stores of aetheryte. All of the above are of substantial value to those willing to pay, though as these ruins are more of a gamble, scavengers can go months without finding anything of note.

The holy grail of a scavenger is a hulk, and anyone hearing about one of these will be quick to enlist in a crew if they think they can survive. Hulks are enormous chunks of monolithic skyships of ages past, certain to contain riches far greater than any ship can carry even if they've been plundered before. While some of these such as the appropriately-named Barohaven, an ancient skyship-turned-refugee colony, have been thoroughly gutted and even repurposed, the vast majority are unexplored or only partially explored. These are the largest known surviving pieces of pre-Cascade civilization, tending to drift relatively quickly through the skies, which is theorized to be part of the reason the structures survived in the first place. The treasures to be found are quite literally unheard of, but so are the dangers: few living nowadays truly know what dangers might lurk in the depths of a strange and alien hulk.