Underworld River

Just be thankful Charon is over his singing gondolier phase.

In works where The Underworld or afterlife is visited, there is often a river present. This river, an Underworld River, typically acts as a barrier between life and death. Some works will treat the river as the afterlife itself. The river is usually a physical feature of some form, but they don't always have to contain water. It could contain a bunch of trash floating through the "air". It could even be made from tortured souls, liquid fire, or boiling blood.

It's typically a metaphor for crossing a threshold, and moving on to the afterlife. Though water is also often linked with purity or cleansing, so crossing or immersing oneself in the river could be a metaphor for a cleansing of the soul.

The river also serves as a boundary, physical or otherwise, between the land of the dead and the land of the quick. It is often the first of many, typically just in front of or behind the gates of the underworld proper. This is often why these rivers run with deadly waters or are home to terrible creatures, as they serve as an explanation for why the dead do not come back to the world of the living, and why the living cannot easily jaunt down to the dwelling places of the dead.

This trope is Older Than Dirt; most examples draw inspiration from Classical Mythology and rivers within the Realm of Hades, such as the Styx, flowing through and demarcating the afterlife, but it's older than even that. Mesopotamian Mythology had the concept of Abzu, a large body of freshwater that was deep below ground, but still above the underworld.

Expect The Ferryman to appear to convey the protagonists across the river, and if they aren't truly dead, have them attempt to either escape themselves, or be Rescued from the Underworld.

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Examples:

Anime & Manga

• Hell Girl: Whenever Ai sends someone to Hell, they find themselves in her ferry as she rows them to the shore.
• The Laws of Eternity: When the gang arrives into the fourth tier of the Spirit World, God Eagle takes them to River Styx, where people with threads tied around them swim through it after dying. He then explains that the threads are silver cords connecting the spirit to the mortal body, cut 24 hours after the heart stops. Moreover, those who refuse to let go of their mortal attachments end up sinking.
• Ranking of Kings: In Episode 19 Kage is stabbed by Ouken, then sees his diseased mother on the other side of the river and tries to take a boat. Miranjo stops him and asks if he's really sure to go without being able to return, and Kage tells his mother that he has unfinished business and needs to go back. Later Shiina and Miranjo's mother show up in attempt to persuade Miranjo from her crimes, but she rejects them and leaves as well.

Fan Works

• The Fairy Sapphire: A strait separates the afterlife, the realm of unborn children, and the present world. Father Time crosses it on his boat (together with the souls he brings to be born or takes to the afterlife), while the main characters use magically-constructed bridges.
• With This Ring: The river Lethe is used by Hades to remove the memories of souls who choose reincarnation. However, during one of Paul's visits to Erebos, he finds Hecate and Eris hosting a pool party to celebrate finding a way to purify the water — with the by-product being a potent mind-wipe residue.

Literature

• The Divine Comedy:
  • In Inferno, Dante crosses the various rivers as he progresses down the pit of Hell. As these entirely surround or compose the Circles of Hell, they are circular flows without source or mouth.
    • Acheron forms the boundary of Hell itself, and can only be crossed with Charon's boat.
    • The dirty, stinking waters of the Styx form the Fifth Circle, where the wrathful and the sullen lie gurgling and struggling in the swamp. Another ferry — Phlegyas', this time — is needed to cross it to the walls of Dis and the lower parts of Hell.
    • Phlegethon, a river of boiling blood, forms the first ring of the Seventh Circle. The violent against others are damned to its heat, with their depth depending on the degree of the violence that they committed.
    • Finally, Cocytus is a lake of ice in which traitors are imprisoned at the very bottom of Hell.
  • Purgatorio finishes the traditional count with the Lethe, which allows the memories of penitents to be purged of sin. It springs from the top of Purgatory, before flowing down to add its now sin-laden waters to the ice of Cocytus. Dante adds another river, named the Eunoe, which performs the opposite function by strengthening the memory of one's good deeds.
• Dragaera: The Deathgate Falls flows from a mundane river into the Paths of the Dead, the spiritual otherworld where souls are judged in between reincarnations. It's common Due to the Dead to send bodies over the Falls; living people can also enter the Paths that way, but the Falls are an Eldritch Location of no fixed height and they don't allow a return trip.
• His Dark Materials: An unnamed river in the underworld is crossed by Lyra and Will in The Amber Spyglass, forcing Lyra to leave behind Pantalaimon, as daemons cannot exist in the underworld.
• The Hunchback of Notre Dame: When officials find the disfigured Quasimodo among the foundlings left outside the Cathedral, one remarks that he must have been found "on the banks of the river Phlegethon".
• The Kane Chronicles portrays the uppermost layer of the Duat (Ancient Egypt's underworld) as a mystical river that exists beneath reality, like molten rock beneath the crust of the earth. The Kane sibling's second direct experience with Egyptian magic involves them using it to cross the Atlantic from England to New York in mere minutes.
• The Locked Tomb: There's an extradimensional space "below" reality which is called "the River". Necromancers who practice soul magic draw power from the dead that end up here, though some believe that it's a transitory realm and not the actual afterlife. It can be used for faster-than-light travel, but doing so is incredibly dangerous, as astral projection is required to survive the trip, and ghost and revenant attacks are an inevitability. The River appears to be horizontally infinite, but it has a riverbed studded with vast mouths that open into Hell.
• The Old Kingdom: The Afterlife Antechamber is a freezing river with a strong current, divided into nine precincts by nine gates. The Abhorsen bloodline is responsible for banishing the undead through the Ninth Gate, past which there's no return, but those that don't make it all the way can crawl back out into Life with disastrous results.
• Percy Jackson and the Olympians: Styx, the river that separates the Underworld from the world of the living, is encountered and referenced multiple times. Its water will kill most beings that try to cross it, but those that can withstand it are made physically invulnerable except in one singular spot. Also mentioned are the Lethe, whose waters drain memory, and the Phlegethon, which runs with liquid fire. In The Heroes of Olympus, these rivers, alongside Acheron and Cocytus, are described as serving as something analogous to blood vessels for the world-body of Tartarus.
• Ravirn: The River Styx marks the official border between Hades (the location) and the rest of Olympus. Also, there's a branch of the river Lethe, where souls can jump in to forget their previous life and be reincarnated into a new one.

Live-Action TV

• Samurai Sentai Shinkenger/Power Rangers Samurai: The Sanzu river is a giant river which flows through the Netherworld and is in a hell dimension connected by cracks to the human world. The river consists of human tears and when monsters attack the human world it causes it to overflow.
• Star Trek: Voyager: In the episode "Barge of the Dead" B'Elanna Torres believes herself to be riding on a barge to Gre'thor (aka Klingon Hell) on the underworld river leading there after a shuttle accident in which she had been seriously injured.

Mythology & Religion

• Christianity: In Dialogues by St. Gregory the Great, one of the visions of the afterlife includes a river of fire one had to cross to get to Heaven. Virtuous souls cross the bridge over the river easily, while the more sinful ones find themselves in trouble. Stephen, who is not very virtuous but not too evil either, slips on the bridge, and demons try to drag him under, while angels strive to keep him on the bridge — at that moment, the man observing it returns to his body and never sees the outcome of the battle.
• Classical Mythology has an entire geography of the Underworld; notable among its tributaries are the Styx, the Cocytus, the Phlegethon, the Lethe, and the Acheron, the last of which is an actual river in Greece that was believed to flow into the Underworld.
• Egyptian Mythology featured a river that Ra took across the sky in a ship; when the sun set, Ra died as the boat followed the river's current through twelve hours of the Underworld.
• Hindu Mythology: The Vaitarani is a river that exists between the Earth and the infernal Naraka, and is said to be capable of purifying sins. The righteous are stated to see a river of nectar, while sinners will see blood.
• Japanese Mythology:
  • The Sanzu River must be crossed by the departed before they are allowed into the afterlife. Similar to The Ferryman, the dead must bring a form of currency (traditionally six mon) before they are sentenced to cross either by crossing a bridge, fording the river, or being forced to swim across a deep stretch of snake-infested waters. Which path the departed take reflects the weight of their offenses that they committed while alive.
  • The Sai no Kawara ("Riverbed of Death") acts like a purgatory specifically towards children who have died too soon to properly cross over to the realm of the Dead. The guardian known as Jizo must protect the children until they are worthy of crossing by keeping them safe from the Oni that prowl the shoreline.
• Norse Mythology:
  • Gjöll is the river that separates the living from the dead in Norse mythology. It is one of the eleven rivers traditionally associated with the Élivágar, rivers that existed in Ginnungagap at the beginning of the world. According to Snorri Sturluson's Gylfaginning, Gjöll originates from the wellspring Hvergelmir in Niflheim, flowing through Ginnungagap, and thence into the worlds of existence. Gjöll is the river that flows closest to the gate of the underworld. Within the Norse mythology, the dead must cross the Gjallarbrú, the bridge over Gjöll, to reach Hel. The bridge, which was guarded by Móðguðr, was crossed by Hermóðr during his quest to retrieve Baldr from the land of the dead.
  • The Sliðr (Slidr) and Nástrǫnd rivers are found within Hel itself and are particularly nasty, as they are the destined resting places for the worst and most loathsome of the dead. The waters of the Sliðr are said to be filled with knives and swords and flows through valleys of poison, while those accused of adultery, oathbreaking, and murder in life must wade in the Nástrǫnd's poisonous waters as the dragon Níðhöggr hunts them down to chew on their corpses.
• Welsh Mythology: The dead were believed to reach Annwn by crossing the River Severn, which separated the worlds of the living and the dead.

Theatre

• Hadestown has a unique depiction of the Styx; instead of being a river, it's a "river of stones" that serves as a wall between reality and Hadestown, being built up by the dead who labor at it.
• The Lightning Thief has the main trio venture across the Styx during the song "DOA", where Charon talks about all of the great musical talent that is in the underworld, such as James Brown, Kurt Cobain, Janis Joplin, and Mozart.

Tabletop Games

• Dungeons & Dragons: The Styx runs through the entire span of the Lower planes and as such is constantly fought over by the forces of the devils and the demons. Its waters drain memory, and as such traversing it requires the services of a specialized order of daemonic boatmen; there are also a few types of monster that can withstand its waters and thus live in its depths, such as a species of serpentine dragon. It has a counterpart in the Upper Planes in the form of the (much safer) river Oceanus.
• Geist: The Sin-Eaters: The Dead Dominions of the Underworld are separated by rivers of strange substances, from boiling water to live scorpions, that grant Power at a Price to people who drink from them. They're more than a physical barrier — people like Sin-Eaters can cross a limited number of Rivers per visit to the Underworld with their own magic, but must barter with a Ferryman to take them deeper.
• Magic: The Gathering features the River Tartyx as a barrier between the world of the living and the underworld on the Ancient Grome-inspired plane of Theros.
• Pathfinder:
  • The River Styx originates in the Neutral Evilinvoked afterlife of Abaddon and flows through all the non-Good Outer Planes. It's a dangerous option for Dimensional Travelers — the waters are deadly, the denizens are predatory, and the only Ferrymen are powerful daemons who like to renegotiate the fee mid-ride.
  • The River of Souls comprises all the spirits of the newly dead, flowing through the Astral Plane to the Boneyard where they're sent to the appropriate afterlife. It's heavily patrolled by Outsiders of all kinds, some to guard the souls and others to waylay or devour them.
• Villains & Vigilantes has a villain team, the Hellons, whose theme is the members all being named after these (Styx, Phlegethon and Lethe).

Video Games

• Afterlife (1996): Both heaven and hell are divided up semi-randomly by large rivers. They're mostly just an obstacle, requiring the player to build and maintain ports to get SOULs across, but they do have a niche use for efficiently spreading Ad Infinitum energy. As is typical of the game, they also come with cutesy descriptions.
  "If you should find yourself in Hell, for gosh sakes, DO NOT ATTEMPT TO SWIM IN THE RIVERS! Besides being dank, smelly, disease-infested, stagnant, and crawling with all sorts of unnamable serpents, they also tend to burst into flames at a moment's notice."
  —"Hell on 30 Pennies a Day"
  Perdition Press
• Akuji the Heartless: Right in the very first stage after he was slain, Akuji must cross Cocytus, the River of Souls, to locate Baron Samedi and make a pact to return to the plane of living. There's another stage where Akuji crosses the River Louth by summoning an expy of Charon.
• Assassin's Creed: Odyssey: The DLC Torment of Hades is set in Tartaros, where naturally, the Styx is featured as part of the map.
• Elden Ring: Those Who Live In Death have a strong association with water, such as the Tibia Mariners that appear in flooded areas. An endgame area, Mogwhyn's Palace, has several zombified or skeletal enemies and is situated underground, atop a lake of blood.
• Fallen London: If your Wounds reach 8, your character will temporarily die and end up on a boat traversing a river with a skeletal boatman and lots of other dead souls being ferried across. You can reduce your Wounds value and return to the land of the living by playing games like chess or dice with the boatman, or by drawing cards that, among various other options, let you trail your hand in the river of the dead and recall your living existence.
• Final Fantasy XIV: In Eorzean mythology, the Heaven of Water, where scholars, inventors, teachers, and entrepreneurs are thought to go after their deaths, has an enormous river running through it. The myths dictate that the river was created when Nymeia melted a star before Thaliak poured the essence of knowledge into it to fill the minds of all people. In the Myths of the Realm raid series, Thaliak will weaponize the river as he battles the party on top of it.
• Hades: Four rivers are featured — the Styx in Tartarus and in the Temple of Styx, the Phlegethon in Asphodel, the Lethe in Elysium, and Oceanus on the surface. Each of them has fish that can be caught as part of the game's Fishing Minigame. Zagreus, being a Cthonic god, is always reclaimed by the Styx and dragged back down to the House of Hades, even if he beats his father in combat. The Acheron is also briefly seen during Charon's Shoplift and Die boss fight.
• Hellblade: Senua's Sacrifice: A late-game area sees Senua trudging through a river of blood in Hela's realm, fighting off hordes of Northmen.
• King's Quest VI: The Styx appears, and its waters are required for one of the game's spells.
• The Legend of Zelda: Ocarina of Time: Invoked. A set piece in the Undead-themed Shadow Temple involves Link fighting off monsters while riding on a ship which eventually sinks into the "river", revealing it to be a void that's filled with mist to give the appearance of being on water.
• Phlegethon: Right off the start, you're unexpectedly banished from the world of living to the banks of Phlegethon, one of the five rivers running through Greek Hell, whose shores are filled with the undead as well as Nazis for some reason. The entire game revolves around your attempts to cross Phlegethon.
• Runescape has the River Noumenon that flows through its underworld. First seen in the 2015 Halloween event, it flows under a bridge behind Death's Office and encircles the City of Um, which is a location central to the Necromancy skill.
• Super Paper Mario: The Underwhere, the land of the dead, is bordered by the river Twygz (a pun on "Styx", "sticks", and "twigs"). Its waters are not directly harmful but are inhabited by grasping, skeletal hands, and as such crossing it requires using the ferry of the boatman Charold.
• A Total War Saga: TROY: The battle against Cerberus is fought on the shores of the river Styx. In battle, the hound of Hades can also summon the fires of Phlegethon to create bursts of flame among enemy soldiers.
• ULTRAKILL:
  • As per The Divine Comedy, the Fifth Layer, Wrath, has the Styx, which would usually bring in the souls of those that died and be part of several punishments. However, the apocalypse that ended mankind was so sudden and thorough the whole layer was Biblically flash-flooded by the sheer amount of incoming souls, and the river is now an actual Ocean Styx, with millions upon millions of Wrathful damned fighting each other for air. The Ferrymen had to upscale appropriately, and their boats are now the size of cruise ships.
  • The Seventh layer of Violence, specifically the 1st ring where it's an eternal warzone, has the blood river Phlegethon as well, though it's much less relevant to your voyage down; the closest you come is roaming the scattered ruins of Urban Warfare lining its shores, trying not to fall inside no matter how many Hellbound war machines come for you.
• Xena: Warrior Princess: Xena was Dragged Off to Hell by the evil goddess, Kalabrax, and must cross the River Styx to find Hades and get him to release her. Naturally it's depicted as a river of lava that kills Xena if she falls in, she can only cross the river by hitting an out-of-reach bell using her chakram and summon The Ferryman.

Webcomics

• In A-gnosis' comics on Greek myth, the river Acheron flows into the realm of Hades from caves in the living world. In Nekyia, a priestess follows the river to visit Hades, catching a ride from Charon along the way.
• Punderworld: The River Styx flows under the living world and leads into the Underworld. Gods drink her waters when making oaths, if they break their word the water within them kills them. The Styx is also a primordial goddess whom Hades is friends with, opening the earth for him and Persephone when their flying chariot goes out of control.

Western Animation

• The Real Ghostbusters: "Hanging by a Thread" features the River Styx itself, a river that runs through the Netherworld (an Eldritch Location full of ghosts and demons).
• The Simpsons: In "Tales from the Public Domain", a retelling The Odyssey has Odysseus (Homer) crossing the River Styx, where a bunch of skeletons are rocking out to "Lady".
  Homer: Oh, this truly is Hell!

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