Source: Exploring Eberron

The storms of the Thunder Sea are legendary. Beyond wind and rain, tales speak of maelstroms that drag down even the largest vessels and masses of vegetation that rise from the water to entangle ships. All of these are very real threats, even more so because these dangers don’t obey simple laws of wind and water. The Thunder Sea is home to a wide range of manifest zones, but the most powerful and numerous are those tied to Lamannia. The endless fury of the First Storm lashes ships with lightning and storm winds, and great maelstroms can pull a ship down into the Endless Ocean. The vast masses of vegetation are tied to the Twilight Forest, fueling unnatural growth that can latch onto a vessel and trap it in the sargassum. Though the influence of Lamannia is most strongly felt here, it’s also possible to find an unexpected region of icebergs surrounding a manifest zone tied to Risia, boiling waters around a Fernian zone, or a region tied to Mabar where the shadows of sailors turn on the living.

As any skilled ocean navigator can tell you, manifest zones are stable, physical locations. While a manifest zone’s influence extends beyond its focal point, the worst storms of the Thunder Sea remain confined to specific areas. However, when the plane linked to a manifest zone is coterminous, its impact is dramatically enhanced, with storms extending beyond their usual radius and becoming far more powerful. This is why knowledge of the sea is vitally important for sailors; if you venture off the approved trade routes, you need to chart a course that will avoid the storms.

Lamannian manifest zones often release elementals into Eberron. An eternal storm may contain air elementals, while water elementals can be found in the region around a maelstrom. Such elementals aren’t intentionally cruel, but they’re driven to express their elemental drives—which often makes them dangerous to ships, which they perceive as alien invaders. Manifest zones can also produce dire beasts—octopi, sharks, and other creatures of remarkable size.

The merfolk of the Thunder Sea (discussed in more detail later in this section) serve as planar shepherds, tending manifest zones and helping to contain and mitigate their effects. This isn’t absolute; the merfolk can’t entirely disperse the power of the First Storm, or stop the growth of the Twilight Forest. But they seek to direct it, choosing to vent its power at times when there is minimal danger to innocents. Even when a region has especially bad storms due to a manifest zone, those storms could be far, far worse if the merfolk stopped performing their rituals or were driven away entirely.

Source: Exploring Eberron

The greatest wonders of the Thunder Sea lie deep below the surface, all but unknown to the people of Khorvaire. The kar’lassa are enormous beasts—miles in length—half-buried and sleeping in the floor of the Thunder Sea. Not even the dragons of Argonnessen know the origin of the kar’lassa. They’ve slept since the beginning of recorded history, and are immune to all forms of divination magic. They could be creations of Khyber trapped before they could rise to the surface, or they could’ve been crafted by Eberron to guard against some future threat. Perhaps they are young progenitors, and when they finally wake, they will create new worlds.

All that’s known for certain is that the kar’lassa are massive, immortal monstrosities . . . and that each is bound to one of the planes. Each kar’lassa radiates the effects of a powerful manifest zone, extending up to 13 miles. The appearance of each kar’lassa reflects the plane they’re tied to; the kar’lassa of Shavarath is a massive draconic beast with steel scales, while the kar’lassa of Fernia is a serpent of embers, water forever boiling against its skin. But the strangest aspect of the kar’lassa is their dreams. As described in chapter 5, when mortals dream, their spirits are usually drawn into Dal Quor. However, when the kar’lassa dream, they don’t dream in Dal Quor. Instead, each kar’lassa dreams in the plane it’s tied to— and more wondrous yet, each great dreamer draws in the spirits of dreaming mortals. Any creature that dreams within 13 miles of a kar’lassa—including unwary sailors passing above, if any are bold enough to go off the approved travel routes—is pulled into the behemoth’s dream, instead of dreaming in Dal Quor. So, for example, anyone who sleeps in the Dominion city of Hal’iri dreams their dreams in Irian. While dreaming in this way, a creature is only present as a spirit, and is immune to the negative environmental effects of that plane; so a mortal dreamer isn’t hurt by the extreme heat of Fernia or the cold of Risia. Even if a dreamer dies in their dream from other causes, they just wake up. This is still dreaming; unless the dreamer is capable of lucid dreaming, they have little control of their actions and will likely only remember fragments of the experience. But if they do have tools or training that allow lucid dreaming (as with the uul’kur in chapter 7), this can be an interesting way to explore the planes.

Twelve kar’lassa have been discovered; one for each plane, aside from Dal Quor. The sahuagin of the Eternal Dominion have built their largest cities around eight of these great dreamers, though they’ve shunned the kar’lassa associated with Mabar, Xoriat, Thelanis, and Risia. The sahuagin harvest biomatter from the kar’lassa, and these substances are the fuel that drives their industry.

The kar’lassa are a source of wonder, not monsters to be fought. To all tests, they appear to be immortal, and regenerate damage quickly. Spells such as stone to flesh or disintegrate only work on a tiny sliver of the kar’lassa, and even that’s quickly restored. If one of these ancient slumbering monstrosities were to rise, it would be an almost unstoppable force of destruction, and destroy the Dominion city in the process. If one of these vast creatures emerged onto land, it could easily devastate cities without even meaning to.

Titanic, unstoppable monstrosities that could threaten entire cities? That sounds a little like the tarrasque. And indeed, a simple way to introduce the tarrasque into Eberron is to present it as a kar’lassa rising from its slumber and threatening Sharn or Stormreach; just add the effects of a manifest zone to the region around it. The tarrasque is small for a kar’lassa; most are miles long, large enough that the sahuagin build cities around them. But it’s possible a small kar’lassa might be the first to wake—can the heroes who oppose it find a way to return it to its slumber before the others wake? If a DM chooses to explore this plotline, they’ll have to decide the truth about the origins of the kar’lassa. If they’re the children of Eberron, they might not want to destroy innocent creatures; they could have an important purpose as yet unfulfilled. On the other hand, if they’re tools of the overlords or the Devourer, their rising will spell disaster.

Kar'lassa, Dar, Kalashtar, and Elves

When the dar dream, they are drawn to the Uul Dhakaan, the shared dream of the empire—but when anyone dreams within 13 miles of a kar’lassa, they’re drawn into its dream. So what happens if a golin’dar dreams near a kar’lassa? These ancient primordial forces trump the work of Jhazaal Dhakaan, and the dar are pulled into the dream of the kar’lassa instead of to Dal Quor. However, all of the dream-tools crafted by the Kech Dhakaan—the kra’uul and uul’kur— function normally within the dream of a kar’lassa.

What about kalashtar? Their connection to Dal Quor has been completely severed, but they do dream; when a kalashtar sleeps, they create dreams within their own mind, drawing on their memories and their quori spirit. However, if kalashtar find themselves within the range of a kar’lassa, they’re pulled into its dream, as with the dar.

The sea elves of the Valraean Protectorate are aware of how the kar’lassa influence the dreams of “lesser” races. Though the Protectorate hasn’t yet captured any Dominion cities, they take great pride in their belief that because they don’t sleep, they would be above the influence of the kar’lassa—but this belief is wrong! It’s true that elves trance rather than sleep, entering a deep meditative state much like a lucid dream, self-directed and untouched by the influence of either Dal Quor or a kalashtar’s quori spirit. However, this process is physiologically similar to a human’s dreams and can likewise be hijacked by the kar’lassa—which would be a startling experience for an elf who’s never dreamed before!

Source: Exploring Eberron

The Thunder Sea is vast and ancient. The sahuagin call their civilization the Eternal Dominion, but in truth, it’s risen and fallen multiple times. The Lurker, as well, has nearly risen several times, and aboleths have set the sea devils against one another in vicious civil wars. There are a handful of storm giants in the depths, but any nation they once possessed was destroyed long ago. Remnants of these conflicts are spread across the Thunder Sea. Explorers could find an ancient temple haunted by the ghosts of the storm giants that built it, an overgrown sahuagin fortress from a previous age of the Dominion, or the tomb of a dragon sealed tens of thousands of years ago.

Most dangerous of all are the deepest abysses, strongholds of the surviving servants of the Lurker in Shadow. These cracks in the ocean floor might hold mighty artifacts forged during the Age of Demons, but they’re home to aboleths, fiends, and even more terrifying creatures.

Source: Exploring Eberron

What might a vessel find if it leaves the sanctioned trade routes and ventures into forbidden territories? The Thunder Sea Surprises table provides a few possibilities.

Thunder Sea Surprises

Source: Exploring Eberron

When dealing with the Thunder Sea, remember that it’s just as civilized as the Five Nations. It does have wilderness regions with feral beasts roaming at will, and you might find wild plesiosaurs, a scheming sea hag, or a hungry scrag. But in the areas above and around sahuagin city-states, such beasts have been tamed or destroyed. All cultures of the Thunder Sea farm fish like the people of the land farm sheep or cattle; a pod of whales may be carefully managed and cultivated, and their farmers will be quite angry with dryskins who poach their ichthyic livestock. There are sharks—and giant sharks—in the wild waters, but in the civilized zones, the sahuagin use them much as humans use hounds. Dragon turtles serve different roles depending where they’re found; in the Dominion, dragon turtles are forced to serve as beasts of burden and living engines of war, while the merfolk form alliances with dragon turtles and consider them partners in a community.

Later sections explore the relationships between the major cultures of the Thunder Sea. Here’s general information about other sentient aquatic creatures in the region:

Locathah are subjects of both the Valraean Protectorate and the eastern regions of the Eternal Dominion. The locathah never had a civilization as advanced as the sahuagin, and have been subjects of the Dominion for thousands of years. However, there could be bands of free locathah on the edges of the Dominion, potentially hiding in the territorial waters of Khorvaire.

Storm giants once had a presence along the coastline of Xen’drik. After devastating conflicts with several sahuagin nations, they were all but wiped out. Today, they’re generally known only through the ruins and tombs they left behind, usually protected by powerful magic and left alone by the Eternal Dominion. There are still a few storm giants in hiding; most are shadows of their former glory, but there may still be a few hidden giants who have preserved their ancient powers.

Dragons have much the same relationship with the Thunder Sea that they have with Khorvaire. There are a few rogue dragons (black, bronze, green, or gold) who pursue their personal goals in isolated regions of the Thunder Sea. Elsewhere, the Chamber monitors the Dominion just as it watches humanity, intervening only if its interests are threatened.

Kuo-toa have no significant presence in the Thunder Sea, though they are found elsewhere in Eberron.

Koalinth were developed by the goblinoid Empire of Dhakaan to defend the coastline, though the dar never sought to cross the sea. These aquatic hobgoblins were exterminated by the sahuagin following the collapse of the empire, though koalinth tribes are occasionally discovered in remote locations. It’s possible a more sophisticated clan of koalinth went into deep seclusion at the same time as other Kech Dhakaan; if so, this could be an interesting ally for the Heirs of Dhakaan.

Venturing underwater can be a challenge for adventurers. They’ll need assistance just to be able to breathe. Chapter 5 of the Dungeon Master’s Guide presents additional rules for underwater adventures; swimming is exhausting, it’s hard to see underwater, and many attacks suffer disadvantage. At the same time, it can seem as though things aren’t limited enough. Shouldn’t something strange happen when you generate lightning damage underwater? Shouldn’t spells that deal cold damage freeze the water? And even if you can breathe underwater, if you go to the depths where the sahuagin are, thousands of feet under the surface, won’t the pressure crush you?

It’s certainly possible to come up with more complicated rules that address all scientific concerns. But ultimately, the goal is to have a fantastic pulp adventure, not to realistically model a deep-sea dive. So it’s okay to follow the rules in the Dungeon Master’s Guide and not worry too much about the science—perhaps the magic allowing you to breathe underwater also protects you from changes in pressure.

Ghosts of Saltmarsh also presents extensive options for running ocean adventures; many of these may offer inspiration as you build your undersea world. Regardless of the rules you decide to use, remember that the Thunder Sea isn’t on Earth. In addition to the environmental effects of manifest zones, you have the aftereffects of conflict between giants, dragons, and archfiends. You have flora and fauna that don’t exist on Earth, which have their own effects on the environment. A story should focus on creating an interesting, exciting environment to explore, even if it isn’t a realistic match for true marine ecology

Q: In Exploring Eberron, the Kar'lassa are described as hijacking the dreams of mortals to pull them into their own dreams, which take place on another non-Dal Quor plane. Mortal dreamers do not have any more control over this than a regular dream, and appear in the plane only as spirits. I have a few questions related to this.

What does this mean for the immortals on that other plane? Are they aware that every night hundreds of thousands of sahuagin consciousnesses are flooding into the City of Brass, or the Immeasurable Market? Are these dreams affiliated with a specific place like that, or are dreamers scattered all over the plane? Do immortals have any way of interacting with these dreams?

So, my vision of it is that as the Kar’lassa are ALWAYS dreaming, their dreams occur in a static location in the linked plane. Spirits of mortal dreamers go to that location. The Kar’lassa have been dreaming since the beginning for creation, so the local spirits are very aware of this. They know there are going to be tens of thousands on mortal dreamers in the location. At the same time, the vast majority of those dreamers are NOT lucid dreamers. They don’t arrive with a clear agenda and they’re going to forget whatever happens. Over the course of a hundred thousand years the locals will have adapted to their presence, either avoiding them or incorporating the mortals into the expression of their idea. With that said, the presence of the Kar’lassa is a factor. It IS the Kar’lassa’s dream, as expressed within the concept of the plane. So I wouldn’t tie Hal’syra to the Immeasurable Market because the Kar’lassa wouldn’t dream about a market full of little creatures. I’d see it as being more likely to dream of an ocean in the sky, with creatures swimming through the air, endlessly tranquil and peaceful — while Hal’shavar would dream of an endless undersea battle, possibly being fought by immense leviathans (including the Kar’lassa itself!), though they could be supported by little creatures… including dreaming sahuagin.

So I personally wouldn’t put Hal’syra’s dream in the University itself, because the University doesn’t feel like something a massive leviathan would dream about. BUT I could imagine any of these possibilities…

… It dreams of the sky-ocean, but there are serene immortals who drift through the sky-ocean like jellyfish, who are willing to share their wisdom.

… it dreams of the sky-ocean, but there is a massive dragon-turtle in the sky-ocean who has a city built into its shell, and that city contains a library.

… it dreams of the sky-ocean, but the lucid dreamers of the Ta’har have found a path that allows their most adept dreams to leave the sky-ocean and reach the University. Merging these ideas together, the turtle-city could contain a back door into the University if a dreamer knows how to activate it.

Q: So the kar'lassa don't dream in a place on the plane so much as create their own?

That's what makes it a DREAM, and not just astral projection. When you dream in Dal Quor, you don't just drop in on the Draconic Eidolon or il-Lashtavar. Unless you are affected by something like a hanbalani or the Uul Dhakaan, you shape a dreamscape that blends your memories and experiences with the broader collective unconscious of Dal Quor itself. The Kar'lassa are DREAMING, and so it's the same process—blending their experiences with the collective nature of the plane. Thus the dream of Hal'syra will be a dream of peace and the dream of Hal'Shavar will be a dream of war, but it will still be a Kar'lassa dream. I don't have time to examine each plane and make suggestions, but hopefully the ideas I've given above provide some inspiration. 

Source: May 2024 Q&A

Whether by sea or air, a journey to Xen’drik is typically risky. Ships heading to Stormreach must brave the sahuagininfested waters of the Shargon’s Teeth island chain and the frequent storms (including the occasional hurricane) that batter the Skyfall Peninsula. The Getting to Xen’drik table provides information on the journey from Khorvaire to Stormreach, including duration, the cost per traveler, and how frequently vessels of any given type depart.

Means of Travel

A trip aboard a Lyrandar wind galleon is quite different from a journey in steerage on a Zil merchant vessel, and for those who can afford it, even faster and more reliable methods of travel can be found. Sea travel, flight, and teleportation are the three primary means of reaching Xen’drik. See the EBERRON Campaign Setting and Explorer’s Handbook for more information on any of the methods and vessels presented below.

Travel by Sea: The Windwrights Guild of House Lyrandar dominates the sea trade, and traveling under the Windwright flag provides an assurance of quality and competence. Every nation has its independent merchants, though, and Zilargo and Riedra in particular have sizable fleets in the Thunder Sea. Cargo ships travel to Stormreach from all the Khorvaire ports mentioned on the accompanying table.

Without the benefit of magic, it takes a ship just over a month to complete the journey from Sharn to Stormreach, assuming it survives the dangers of the Thunder Sea. The mundane vessels that make these journeys are mostly cargo ships, built to hold a maximum volume of trade goods. As a result, creature comforts are at a minimum, and passengers are lucky to find sufficient space to hang hammocks. Travelers on cargo runs are expected to help out with shipboard duties and chores, and if the ship comes under attack, they are expected to fight alongside the crew.

Aerenal, Zilargo, and House Lyrandar often make use of soarwood sailing ships. Light and swift, these vessels move at twice the speed of a mundane ship.

The top of the line in sea travel are those vessels crewed by heirs of House Lyrandar. A mundane ship outfitted with a wheel of wind and water can sail at three times the speed of a normal vessel, while an elemental wind galleon can cover up to 480 miles in a day. Such vessels are usually designed with paying passengers in mind, with a few small cabins for travelers.

Travel by Air: The Skyfall Peninsula is well named. The high degree of storm activity makes travel across the Thunder Sea dangerous even for heirs of House Lyrandar. Airship captains have encountered unbound elementals, yrthaks, insect swarms, and more dangerous threats in the Xen’drik skies. As a result, House Lyrandar typically deploys airships to Stormreach only on urgent business of the house or when a vessel is chartered by a favored client. Travel is fast, and airships are designed for comfort, but the cost can be prohibitive.

Teleportation: The safest way to cross the Thunder Sea is also the fastest way: teleportation. Characters who cannot teleport themselves can hire House Orien, but the distance from Khorvaire to Stormreach requires the rare greater teleport ability of an heir of Siberys. Below is the list of cities in which such an heir might commonly be found, along with the cost of the trip and the percentage chance that the heir is available on any given day.

A maximum of five Medium or smaller creatures can be transported in this manner, along with whatever equipment they can carry. Prices assume that the caster is making a return trip over the course of two consecutive days. The PCs can piggyback on the return trip at no additional cost, though any delay must be negotiated with the heir (at rates ranging from 10% to 50% of the above cost per day).

Chartered Ships: For characters with plenty of gold but no time to wait for the next departing vessel, chartering a ship is a good (if expensive) option. Chartering a sailing ship costs 100 gp per day of travel (200 gp per day for a soarwood sailing ship, or 300 gp per day for a Lyrandar sailing ship). Wind galleons can occasionally be chartered for 750 gp per day, while chartering an airship costs 1,000 gp per day if a captain willing to risk the crossing can be found.

Consult the Getting to Xen’drik table for the number of days required for a charter journey. Characters chartering a ship pay the daily rate for travel to and from their destination, plus each day that the ship must wait for the party to complete its mission. Characters chartering a ship must pay for the return trip even if they are not on board. Charter rates include hazard pay for the ship’s crew, but the chartering characters are responsible for hiring guides and making bribes as required (see the Sahuagin of the Thunder Sea sidebar, below).

Luxury Ships: Xen’drik is not the ideal destination for a pleasure cruise, but some people only travel in style. Luxury travel increases the cost of a journey by at least 50% and might be available only on a charter basis (at the DM’s discretion). While on such a journey, characters have access to fine food and entertainment, along with a House Jorasco healer. Between the comfortable furnishings and the ministrations of the healer, characters can regain up to 4 hp per character level per day while traveling. In addition, the luxury vessels of House Lyrandar carry a complement of sentries from House Deneith—passengers don’t pay justfor comfort, but also for peace of mind.

Passengers never have to work aboard a luxury ship, and in case of combat, are not expected to help—although a Lyrandar captain might reward PCs who leap to the defense of the crew. The adventure Voyage of the Golden Dragon presents a series of linked scenarios built around the Sharn-to-Xen’drik maiden voyage of Khorvaire’s newest luxury airship—and the threats, intrigue, and murder that go with it.

Dragon Eels

Dragon eels live in the oceans of Eberron and prey on dragon turtles and sailing vessels. They are most common among the islands north of Xen’drik, where the sahuagin dwell. The relationship between dragon eels and sahuagin is unclear. The sahuagin speak of their alliances with the creatures, but the dragon eels clearly consider the sahuagin to be servants, if not slaves, and guardians of their hoards

Siege Crab

Siege crabs are reportedly the creation of a storm giant wizard who lives deep in the Thunder Sea. These mammoth crabs have attacked ships crossing the Thunder Sea, ravaged miles of coastline on both Khorvaire and Xen’drik, and even preyed upon the sahuagin of Shargon’s Teeth. A siege crab that attacked the city of Stormreach disgorged four chuuls before retreating back into the sea. The chuuls were all slain by the city’s defenders, and no other siege crabs have attacked Stormreach since.

Some heroes look inland toward the jungles and mountains for adventure. Others gaze toward the mysterious Thunder Sea. Below its sparkling surface lies a fleet of sunken pirate ships, their holds brimming with titan’s gold—and the remains of their crews. Forests of kelp hide malenti and their sharklike kin. The kelp forest also shrouds their ancient temples to the Devourer, in which the malenti hold nightly feasts of blood sacrifice to appease their god. Coral fields, wonderlands of undersea light and color, hypnotize visitors. These visions of paradise are treacherous, distracting swimmers from predatory sea serpents and dragon turtles. Deep ocean rifts shade kraken overlords and cabals of alien aboleths from the sun’s prying eye and lure foolish trespassers to a watery doom.

The sea devils are fearsome predators, able to bring martial prowess and magical might to bear on their enemies. However, not every encounter with the sahuagin has to be a battle.

Unsavory Appetites: One of the rituals of the sahuagin religion involves consuming a fallen foe to gain his strength and power. Some sages claim that this process is more than just ceremony, however, and that creatures such as the four-armed mutant sahuagin and the malenti are the result of this rite.

Either while at sea or in Stormreach, the party is approached by a sahuagin priestess. She wants the PCs to go inland and capture an exotic monster that can be found only in Xen’drik—a creature that lives too far inland for her warriors to hunt. She pays handsomely for a live specimen and might hire the party to hunt additional beasts. But what horrors might these creatures produce when consumed by sahuagin warriors?

The Festival: The party is approaching a small port village by boat when someone catches a fl ash of motion in the water. A dozen sahuagin rangers rise from the sea, along with a priestess and a four-armed wizard. This clan has a long-standing pact with the villagers concerning fishing rights and the worship of the Devourer, and this delegation has arrived for the annual rituals. Will the PCs seek to defend the village before learning the truth? How will clerics react to humans who follow the Devourer?

The Words of the Devourer: The deep water of the Thunder Sea holds uncounted secrets. As the party’s ship approaches Shargon’s Teeth, a sahuagin ranger clambers up the hull and onto the deck. He holds a sphere of stone engraved with intricate writing, which he hands to the party. A successful DC 25 Decipher Script check reveals that it is a prophecy—an ancient inscription that clearly indicates the date, the ship, and one of the PCs. The ranger insists that the chosen PC accompany him to a temple deep beneath the waves. A struggle lies ahead, and the character must receive the blessing of the elders if any of the party are to survive.

Is it a hoax, or is danger truly coming? Has a rakshasa rajah been released from bondage, or does the prophecy foretell an alliance of aboleths or some dark plan of the daelkyr? And what wonders will the characters see in the city beneath the waves?

Secrets of Xen'drik

Passage to Xen’drik can be booked only in the major southern ports of Khorvaire. Each city is slightly different, and the tone of the port can add to the flavor of the journey.

Sharn: The largest of the southern ports and the city physically closest to Stormreach, Sharn is known as the Gateway to Xen’drik for a reason. It is a major center of trade for the Windwrights Guild, but all manner of private ships also make their way to Sharn. This is the best place to find passage to Xen’drik on short notice. The prices given here supersede the general information provided in the Sharn: City of Towers supplement.

Pylas Talaear: For the long-lived elves, the slow journey to Xen’drik is a chance to reflect on the trials and exodus of their ancestors. The vast majority of the ships that sail from this port to Stormreach are elven vessels.

Trolanport: The gnomes were exploring the seas long before the first dragonmarks appeared, although a number of Zil merchants have joined the Windwrights Guild. The gnomes have a proud seafaring tradition: Nearly half of the mundane and soarwood vessels leaving this port have gnome crews. Medium creatures find the accommodations aboard such ships to be quite snug.

Zarash'ak: Prospectors of the Finders Guild can always find work in Xen’drik, and House Tharashk has forged ties with House Lyrandar to facilitate travel to Stormreach. While technically part of the Windwrights Guild, many of the sailors who run the Zarash’ak route are actually half-orcs who have come to love the sea.

Exploring Eberron

The Thunder Sea is a critical path for trade. Any traffic with Xen’drik crosses the Thunder Sea. In addition to the ships of House Lyrandar (both elemental galleons with dragonmarked captains and mundane ships licensed by the house), the Thunder Sea sees traffic from Aerenal, Zilargo, Breland, and Riedra. The most important ports include Pylas Maradal (Valenar), Pylas Talaer (Aerenal), Sharn (Breland), Stormreach (Xen’drik), Trolanport (Zilargo), Wyvernskull (Darguun), and Zarash’ak (Shadow Marches).

These major ports see both commercial, diplomatic, and military traffic. Aereni merchants carry shipments of exotic lumber, Riedran vessels are laden with crysteel and dragonshards, Lyrandar ships carry all manner of trade goods, and smugglers sneak barrels of kuryeva and tilxin blood into hidden coves. While the standard map of Khorvaire focuses on these major ports, there are also countless smaller ports and fishing villages scattered along the coastline.

The masters of the Thunder Sea—the sahuagin—don’t want dryskins blundering through their territory. Traveling directly along the coastline is reasonably safe, and local fisherfolk don’t need to negotiate with sahuagin every time they set sail; the sahuagin don’t lay claim to the waters within 6 miles of Khorvaire’s coast, and permit fishing an additional 20 miles beyond that. But crossing the Thunder Sea is an entirely different story. Setting aside the territorial claims of the sahuagin, the sea is filled with deadly hazards—endless storms, demonglass spires, and hungry monstrosities. The Eternal Dominion has established specific routes that captains must follow, safe from hazards and monitored by the Dominion. Captains who wish to use these routes must obtain beacons of passage—common magic items that tell the sahuagin their travel is authorized, charged to last for a set time. Even with a beacon, there are places—such as Shargon’s Teeth—where a wise captain pays for the services of a sahuagin or merfolk guide.

Some brave (or foolish) souls deviate from these approved routes, whether desiring speed or avoiding the cost of local customs and the price of a beacon. The Thunder Sea is nearly the size of Khorvaire itself, and the sahuagin aren’t everywhere; however, those regions shunned by the sahuagin and merfolk are usually avoided with good reason, and smugglers may face dangerous environmental hazards or hungry monstrosities.