The Chasm • Odyssey of the Dragonlords

The Chasm is a massive fissure at the center of the Sunken Kingdom. It stretches down for miles into an abyss that eventually connects to the Nether Sea. The waters of the Nether Sea are steeped in primordial magic and have twisted the sea life here into creatures of immense size and power. The most powerful and dangerous of these creatures is Scylla. Scylla is an abomination. She is the most dangerous creature ever spawned from the Island of Typhon. The Titans released her millennia ago, to help defeat the angel Phaeros and his rogue pantheon of gods. Now Phaeros is trapped in her stomach. She sleeps at the bottom of the Chasm, served by an army of merrow who occasionally feed her sacrificial offerings.

The Chasm has three zones. Each of these zones has a different environment than the other zones and is populated by its own unique set of creatures.

The Upper Reaches#

Light still barely permeates the Upper Reaches of the Chasm, which extends down for the first 1,000 feet. This entire region is considered Dim Light. Standard aquatic life can be found here, including a wide variety of fish, octopus, and squid. These creatures have learned to avoid the huge predators that hunt in the region. Giant sharks are the apex predator of the Upper Reaches. The sharks are descended from the even more massive Cetus (appendix B) that swim in the lower regions of the Chasm.

illustrated quote — Of course there are stories of the Lost Pantheon, but I never imagined that they could possibly be true. For one thing, the songs were quite … suggestive. Let’s just say that the Trickster God of Satyrs got up to some ripe old mischief and leave it at that. —Kyrah, Goddess of Music

The Void (1-Mile Depth)#

Darkness is complete within the Void. The entire region is considered Dark, though Darkvision still works. Eels and squid are found in the inky depths, along with strange fish that can generate light (such as anglerfish and viperfish). This region is extremely dangerous, for massive Serpens and primordial Cetus (both in appendix B) hunt in the waters. The cursed Ichthys (appendix B) crawl along the sides of the chasm and have even banded together into a small and hateful tribe. The only creature that wouldn’t immediately consider humanoid trespassers to be food is a single Dragon Turtle that lairs in a cave.

The Pit (2-Mile Depth)#

The very bottom of the Chasm is pitch black. However, swirls of silvery water occasionally light up small regions of the Pit. These are currents that come from the Nether Sea. The bottom of the Chasm is littered with the decayed corpses of prey killed in the regions above. Whale corpses are the most common, but there are also dead ichthys, merfolk, and other intelligent sea dwellers. The corpses provide food for the only living creature in the Pit—the abomination known as Scylla (appendix B).

Exploring The Depths#

The deepest parts of the ocean are dangerous for many reasons beyond predators. Light becomes a problem once explorers have gone deep enough, but the most difficult obstacle is the crushing weight of the ocean. The impact of water pressure in the depths of the ocean are ignored by creatures with a Swim Speed. However, those without a Swim Speed must succeed on a DC 15 Constitution saving throw every minute they spend in the Void or Pit areas of the Chasm. Failure results in 1 Exhaustion level.

Chasm Key Locations#

All of the narration text assumes that the heroes have some sort of light source or are using Darkvision.

G1: The Upper Reaches#

The faint glimmer of light from the surface dimly illuminates these waters, which teem with aquatic life. Multitudes of small and medium-sized fish dart back and forth, gathering in brightly-colored schools. Larger fish— sharks and other predators—prowl the waters, endlessly searching for their next meal, as octopuses and squid swim languidly by, their tentacles trailing behind.

The Upper Reaches are the domain of Giant Sharks. Anyone swimming in the Upper Reaches has a chance of becoming hunted by a giant shark. The chance is 25% when someone first enters the region, with a cumulative 10% chance for every 10 minutes spent there. A giant shark will attack from below, with Advantage on its first attack. If the giant shark draws blood, there is a 20% chance per round that the blood will summon an additional 1d4 giant sharks.

G2: The Last Plateau#

A massive formation of jagged rock juts out from one wall of the Chasm, forming a flat, protruding ledge that overlooks the inky depths of the Void beneath. Small fishes, eels, and crustaceans weave their way among the beautiful coral structures that cover the rocky outcropping, protected from the currents and the deadly predators looming in the darkness below.

Full-page art, p.287 — Full-page art — p.287

The Last Plateau is so called because it is the last place someone can rest before descending into the darkness of the Void. The coral is home to many fish, eels, and octopi. It is also haunted by the Ghost of a merman named Gorathul.

Ghost of Gorathul. Gorathul makes himself known by possessing fish and octopi and using them to lure explorers to the skeletal remains of his body. He communicates with anyone who comes within 20 ft. of his body. He died decades ago, trying to fulfill a promise to his husband. His husband was cursed by Lutheria and began the painful transformation into an ichthys. He made Gorathul promise to kill him, but when the time came, he couldn’t make himself to do it. Later, when his husband had been lost completely to the transformation, Gorthul followed him into the Chasm to try and fulfill his promise—but he didn’t get very far.

Gorathul will trade information to anyone who swears an oath to end his husband’s suffering. The ghost knows the location of the wise turtle and the ichthys lair. If someone is willing to allow the ghost to possess them, he will travel with them and direct them to either lair. He does not take control but simply acts as another voice in the head of his host.

G3: The Void#

As the light from the surface fades, the water becomes cold and black. As you descend deeper and deeper, the teeming aquatic life of the Upper Reaches gradually gives way to a vast, dark emptiness. Few creatures can survive in these depths, and those that do are fierce and deadly.

The Void is the hunting grounds for two of the deadliest predators in the ocean—the Cetus and the Serpens (both in appendix B). The chance of becoming prey for one of these creatures is 25% when someone first enters the region, with a cumulative 10% chance for every 10 minutes spent there. There is a 1 in 4 chance that the predator is a serpens—otherwise it is a cetus.

The cetus will attack from below like a giant shark. If the cetus draws blood, there is a 25% chance per round that the blood will summon an additional 2d4 giant sharks. The serpens hunts alone and no other predator dares come between the serpent and its prey.

Walls of the Void. Swimming close to the chasm walls is a little safer than swimming out in the open. However, there is a non-cumulative 10% chance every 10 minutes of encountering 1d4 Ichthys (appendix B). The cursed monstrosities attack trespassers on sight.

G4: The Ichthys Lair#

Through the murky waters it is just possible to make out the medium-sized entrance of a cave carved into the side of the chasm. The cramped entrance gives way to an enormous chamber littered with the stark white skulls of numerous sharks and whales, along with the skeletal remains of several humanoids, all picked clean by ocean scavengers.

A dozen Ichthys (appendix B) have built a small community within a cave. The cave opening is 10 ft. wide (small enough so that cetus and serpens cannot enter) and opens up into a large chamber 150 ft. in diameter. Two ichthys always stand guard at the entrance. The other ichthys sleep in clutches of two or three in the chamber.

One of the ichthys sleeping in the cave is the husband of the ghost named Gorathul. All of the ichthys appear to be in constant agonizing pain.

Treasure. At the back of the cave is where the ichthys keep everything of value that they have taken from their victims. The treasure is stored in a giant clam. Within the clam are the following:

Sixty pearls (worth 100 GP each)

Fifteen black pearls (worth 500 GP each)

One vial of Oil of Etherealness.

G5: The Serpent Holes#

Several large, cylindrical holes have been burrowed into the chasm wall in a seemingly random pattern. The perfectly smooth tunnels are twenty feet in diameter, and they extend so far and deep into the bedrock that their terminus cannot be seen.

Each of these holes in the sleeping place for a massive

Serpens (appendix B). The serpens excavate tunnels that extend for thousands of feet, terminating in round chambers where they rest. There is a 1 in 4 chance that an intruder will find a serpens in its lair. There is also a 1 in 4 chance that an intruder will be met by a returning serpens while leaving the tunnel.

G6: The Wise Turtle#

A wide, flat ledge protrudes out from the chasm wall, leading to a massive cave. The fifty-foot-wide, thirty-foot-high entrance to the cavern is guarded by dozens of large stalactites and stalagmites, giving the vague impression of a gaping, tooth-filled maw.

A solitary Dragon Turtle named Umbaroth lairs in this cave. Umbaroth is one of the oldest of his kind, and his shell shows damage from dozens of encounters with cetus and serpens. He mostly stays within his cave, only venturing forth to eat. Over the centuries he has gathered a vast hoard, which he guards jealously.

Corrupted Mate**.** Umbaroth used to have a mate, Nalaxxar, but she was corrupted by Scylla into a monstrosity. If the heroes promise to help him put her out of her misery, he promises to aid them against Scylla. Alternatively, he is willing to help explorers for the right price. For 10,000 GP, the dragon turtle will join the heroes and aid them in battle. The dragon turtle knows all the locations within the Chasm. If Bloodied in a fight, Umbaroth will flee and return to its lair.

Treasure. 55,000 SP and 21,000 GP have been collected into a large pile. Mixed in with the coins are:

A ruby (5,000 GP)

Bracers of Defense

Two Potions of Giant Strength (fire)

G7: Shark Nest#

On a large, sandy ledge extending out from the chasm wall you see several dozen terrifying figures. Dead-eyed giant sharks cluster together, motionless and asleep. Amongst them are also a handful of terrifying sharks the size of whales. Fortunately, all of the sharks are currently resting; peaceful and unaware.

There are a half-dozen Cetus (appendix B) and two dozen

Giant Sharks that sleep on the ledge. Waking these creatures is almost certainly suicide.

G8: The Pit#

The long descent into the chasm has finally reached its end. The sandy, black bottom of the ocean is littered with the rotting corpses of gargantuan whales: leviathans of the deep, brought down by some monstrous apex predator. A smattering of half-eaten humanoid corpses also dot the ocean floor—evidence that whatever horror dwells here will feed on anything.

The pit is the domain of Scylla (appendix B). Every 10 minutes that the party spends in the Pit has a 20% chance of drawing the attention of Scylla.

If the heroes are with Umbaroth, he will guide them to Nalaxxar, being able to smell her scent from anywhere within the Pit. Nalaxxar has mutated to have multiple heads like a hydra. She will attack as soon as she notices any other living thing. She fights to the death.

Scylla. Read the following when the heroes have Scylla’s attention.

The cold, dark waters around you shudder. The silence of the depths is broken by a deep, resonant moan: the cry of an entity both ancient and horrifying. From the gloom, a gargantuan abomination emerges: six serpent-like heads twist and writhe on long necks protruding from a grotesquely bloated torso. The undersea nightmare lurches toward you with terrifying speed, writhing across the ocean floor on twelve monstrous black tentacles, gnashing its hungry jaws.

Scylla (appendix B) is ravenous and will try to eat anything that it comes across in its domain. Scylla is fearless and will fight to the death. Anything that Scylla swallows is subjected to a magical stasis that paralyzes its victims for the process of digestion, which can take thousands of years. When Scylla is killed, the angel Phaeros (CN Solar) will be released from this magical stasis. He cuts his way out of Scylla’s gut and appears before the heroes.

As the horror of the deep finally collapses, its bloated torso suddenly begins to pulse and throb. A thick tearing sound ripples through the waters, and a deep gash appears in its abdomen. The tip of a glowing blade emerges from inside the beast’s belly as someone—or something—carves its way to freedom. Seconds later, the fresh wound rips wide open, and a magnificent winged humanoid crawls out of the monster’s stomach. In his right hand he clutches a mighty sword, while his left hand holds a ball of blue fire that blazes even at the bottom of the ocean. In a voice that booms through the depths, he announces: “The glory of the gods be upon you, brave mortals. By slaying the demonic Scylla, you have freed me to complete my sacred task and restore to power the rightful pantheon of Thylea!” Ignoring any further attempts to engage him in conversation, the angel flaps his mighty wings and shoots upwards, vanishing as he speeds toward the surface.

Phaeros is able to swim using his fly speed. He will fly as quickly as possible to the Temple District of the Sunken Kingdom and ignore any attacks directed at him. He plans to use the Promethean Fire (appendix C) to free the hyperions from their temple prisons. Refer to Freeing the Gods.

G9: Nether Sea Fissure#

A deep, narrow fissure slices its way across the ocean floor. Shimmering silver water seeps from the rift, gently floating upwards until it slowly disperses in the darkness of the ocean depths.

Anyone trying to swim more than 200 ft. into this rift will come under the magical influence of the Nether Sea’s primordial waters. Refer to the Nether Sea chapter for details about this strange liquid.

Treasure. Fifty feet into the rift, there is a great treasure contained within a giant-sized adamantine chest. The chest is locked, and it requires a successful DC 20 Dexterity check using Thieves’ Tools to open.

Within the chest is 3,000 PP. Mixed in with the coins are the following:

Three black sapphires (5,000 GP each)

Six black opals (1,000 GP each)

Mantle of Spell Resistance

Wand of Polymorph

Current. Every round spent in the rift, there is a 25% chance that a current of silvery water from the Nether Sea will wash through.