Some of these portals lead to mighty empires and mercantile kingdoms. Others lead to more esoteric places, like the elemental planes. Yet more could lead to even stranger or darker realms, such as one infested with aberrant horrors.
What separates the Aetherial Expanse from some other extraplanar settings is the amount of worldbuilding that has been added to make the Expanse feel like its own distinct place. The setting isn’t just an excuse for off-the-wall D&D adventures, but rather feels like a real place with a history, established cultures, and clashing ideals.
The Aetherial Expanse has an identity that’s entirely its own. It has a visual language that feels high fantasy and otherworldly yet is identifiable and distinct to the Expanse. There are new ancestries that players can choose for their character that aren’t just unique to the Expanse but only exist because of it, such as the Astral Emergent.
The Expanse doesn’t just feel like a plot device for realm hopping, like an endless corridor of doors that lead to more interesting places. It also doesn’t just feel like a random soup of disconnected ideas and tropes thrown together.
It doesn’t feel so endless and infinite that personal stakes become meaningless in the grand calculus of yet another multiverse. Yet, there is vast room to introduce your own characters, connected realms, and adventuring ideas.
Perhaps your own homebrew world has a portal that opens onto the Aetherial Expanse, unlocking an entirely new scope of adventures for your 5e game. Or maybe you start a new campaign that is specifically about the Expanse, and from there you branch into the genres and stories that interest you the most.
The strength of the Aetherial Expanse is that it’s a beautiful canvas with established colors and textures that make it come alive and feel real. Yet there are still many different types of stories that can be told on its glittering starlit waves, just like the following.
Existential Horror Adventures
What lurks in the deepest darkest regions of the aetherial sea? What aberrant horrors could swim in its depths or exist in the darkness between stars? What danger does the beauty of aether conceal?
The Aetherial Expanse is the perfect setting to contrast its gorgeous and dreamlike visuals with a very dark and frightening secret.
For example, what omen does the appearance of a spectral ghostship portend? What happened to the sailors aboard? Does your party discover that the crew have all disappeared? Yet their voices cry out in tortured unison from something big which lurks in the lowest deck.
Perhaps the sailors’ undead spirits continue to steer the shadowy vessel, captained by a whispering voice only they can hear. You will too if you spend too long aboard.
Your party may discover a new island on the aetherial sea that seems uninhabited at first. Slowly they uncover a hidden species of giant insects or a parasitic biomorph.
These horrific creatures are spilling from a portal to a cosmic realm with a singular will to consume all in their path! Your characters must escape before being devoured by the hive, and before their ship can be used as a way for the swarm to start spreading from the island.
Terrifying aberrations and monstrosities resembling sea monsters may drift above the aetherial sea or swim beneath it, their beauty belying how dangerous they are. Even just the aetherial sea itself is dangerous to mortals!
Swimming in aether can cause fever, hallucinations, and physical transmutation as your body begins to crystalise into aetherium. This process can be at once beautiful and horrifying to behold.
It is believed that the aetherial sea is either the essence of a dead and ancient deity. Being exposed to Aether floods your body with the essence of a god, which it cannot survive. Or stars of the aetheric sea are the billion souls of a punished civilization. When you are immersed in it, you are being torn asunder by those endless spirits.
Clearly the Aetherial Expanse is ripe for tales of cosmic horror. But that’s not all this setting can do, or even what it was initially designed for.
Political Intrigue Adventures
The Aetherial Expanse is famously torn between three main factions. The Karelagne Empire spread from their home realm, intent on dominating other civilizations and seizing their resources. The Kingdom of Ayris is a smaller nation, but their merchant fleet nonetheless spreads across the Expanse, harvesting anything that can be sold or traded. The third known faction of the Aetherial Expanse is not a unified people as such, but rather the pirates, privateers, independent explorers, and common folk that live across the Expanse.
Between these three factions, and more that you can add yourself, conflicts in the Aetherial Expanse can be multifaceted and morally complex. You might play as a band of freedom fighters against the Karelagne Empire’s colonizing expansion. Or you could play as agents of the Karelagne Empire protecting isolated settlements from aetherial monsters and plundering pirates.
Perhaps your own homebrew world has discovered the Expanse for the first time. Now they must navigate the tense politics between the Karelagne and the Ayris, all whilst finding their own footing on the aetherial sea.
When an even greater cosmic threat emerges from the depths of the aether or another plane of existence, your party might be required to unite the individual nations. Such a campaign could include rooting out villains from all nations. These vagabonds could have vested interests in sabotaging an alliance, to the detriment of all.
The point is, there doesn’t need to be designated heroes or villains in an Aetherial Expanse campaign. This makes it the perfect backdrop for a tale of dark morality and political intrigue.
Swashbuckling Pirate Adventures
Of course, the Expanse can also play host to more swashbuckling adventures of pirate kings and charming scoundrels.
You could draw inspiration from a show like Black Sails, which depicts pirates as downtrodden and exiled from civilization for wanting basic freedoms. The show depicts the complex and often violent politics aboard a pirate ship and between pirate captains. Yet it also portrays how an infamous pirate king like Charles Vane or Edward Teech can be at once fearsome yet also humanly flawed.
But you can also take inspiration from the high seas high-jinks of Pirates of the Caribbean, One Piece, Our Flag Means Death, or indeed the trailer for the Aetherial Expanse: Setting Guide! Hunt for buried treasure on long lost islands, harass Ayrissian aristocrats and empty their holds, and sail across the sea of starlight wherever you and your crew decide!
The Aetherial Expanse: Setting Guide provides additional rules for your party to take up specific roles as the crew of a sailing ship and work together to capture a prize! You can buy, steal, or swindle your own boat with its own rules and stats. You can then choose to manage its supplies and furnish it with upgrades.
There are even naval combat rules to punish any Ayrissian frigates or Karelagne warships who dare to come after your crew (something that can also be ported into any nautical themed campaign!).
Starting as part of the crew of a pirate ship is also the perfect way to begin a campaign without “meeting in a tavern”. Being part of a larger group gives the party a great reason to adventure together and an established common goal to work towards.
The history and culture of their pirate crew, and the party’s roles within it, can all be created during a Session 0. The players can even name their pirate ship together! And then the first session of the campaign can kick off with them already sailing the Aetherial Sea in search of its cosmic secrets!
Planar Exploration Adventures
A pirate ship isn’t the only type of vessel that might be sailing the Aetherial Sea. Your party could be explorers with a mandate to discover new and interesting places both on the Expanse and through the realm portals that open onto it.
You could run a campaign inspired by Star Trek, where each couple of sessions a gate to a new and peculiar realm is discovered. Or perhaps the player-characters have heritages from all across the multiverse, with personal quests that call them back home to spotlight a different player each week.
Maybe your party are bounty hunters who take contracts on cosmic criminals. Perhaps you hunt down aetheric monsters that have slipped into other realms, like interdimensional Witchers. Or maybe your exploration uncovers a grand alien threat like Mass Effect?
This planar-hopping style of campaign could result in vastly different types of adventures week to week. One session could be filled with cosmic horror, the next is a western defending a small village from desert raiders, and after that is a treasure heist in the MagiTech city of Karel.
Yet for all its planar-hopping high-jinks potential, the Aetherial Expanse gives your party a distinct home to keep coming back to. The realm between realms.
Alternatively your party may already have a home plane, such as your homebrew setting, or an established realm like the Karelagne Empire. The adventure may then become exploring all the strange and mystical corners of the Aetherial Expanse itself.
The Expanse’s real strength as a planar setting is that it is multifaceted, interesting, and expansive enough to support entire campaigns without planar travel at all. Yet all those portals spilling out onto the Expanse provide limitless possibilities for character creation and the types of adventures that can be run!