Your ancestor lost his mind, obsessed. He and his shipmen slaughtered these beautiful creatures in cold blood. Genocide — That's your legacy.
Helen Hawkins to Ben Pownall

Merfolk (or Merpeople), are a marine race of half-human, half-fish predators who have existed for hundreds of years in secret under the depths of the oceans of Bristol Cove, Washington.

Ian Sutton describes them as "highly evolved apex predators" (although it turns out to be a premonition that Ben forsees when he learns of the consequences of saving Ian).


Bristol Cove was once home to mermaids. Over a hundred years ago, a Siren enchanted the men of Bristol Cove and a Captain, Charles H. Pownall, heard her Siren Song. She emerged from the sea to greet him and he fell in love with her. The Siren and Charles H. Pownall had a daughter that was born in transition and appeared deformed. He took his daughter to the Haida, people who weren't afraid and had them cure her of her deformity. The Siren left, going back to her home in the sea, believed that her daughter was killed, and never returned. The Captain was so bitter and heartbroken that he and his men sought vengeance on the mermaids and slaughtered most of them in cold blood. As the genocide occurred even mothers were forced to watch as their babies were killed right in front of them.

Season 1

Ryn and Donna were racing in the sea one night when Donna was captured by one of the fishermen and brought aboard the ship. She attacked Chris and began to sing her siren song. The military then arrived in helicopters and took her to their military base, where she was placed in a tank and experimented on. Scientists took a sample of her DNA and placed it into a fully paralyzed rat which caused it to be cured and healed.

Donna escaped the military facility and Ryn and Donna finally returned home to the colony.

Levi and Donna attacked Ben and the other fisherman board the ship. They got hurt but escaped.

Donna, Katrina, and Levi came onshore to Bristol Cove. Donna wanted to bring Ryn back to the colony with them, and Katrina and Levi wanted to kill Ryn. Katrina and Ryn fought and Ryn usurped her position as Alpha leader of the colony. After Donna got shot by Xander, Ryn, Levi, and Katrina took her to Helen's home. Ryn then told Levi and Katrina to leave and never return. Unfortunately, Donna died the next morning from the infection in the wound, and her body was buried in a special cemetery commemorated for merfolk who died in human form in Bristol Cove and Helen's ancestors. Ryn, feeling saddened by Donna's death and guilty for ruining Ben and Maddie's relationship, left Bristol Cove for some time.

Season 2

Months afterward, Ryn returned and decided to stay in Bristol Cove, but then something happened out in the water driving away all the marine animals and forcing them out. She later investigated some beached whales with Ben and Maddie and found one of them alive. She then went out to explore where the source of the problem was and found a shipwreck. There, she discovered another mermaid, dead. Then, a sound wave came out and caused great pain to Ryn. After discovering that a ship working for the oil company was using sonar, Ben and Maddie help Ryn recover from the sound waves damage.

Later, Ben, Maddie, and Ryn find another mermaid, who seemingly died while transforming into her human form. Then they found Levi, who barely survived. Unbeknownst to them, Katrina, along with four other merfolk (three mermaids and one merman) returned and found shelter in Helen's house before they, along with Ryn and Levi, were moved to a log cabin out in the woods to avoid possible detection from the people of Bristol Cove. If they show any sign of dehydration, they go to a secret water tank where they can temporarily revert to their mermaid/merman forms. Over time, they slowly become more insinuated amongst the humans as they learn the cultural and social traits of humans; all except for Katrina who still harbors resentment towards humans and Ryn.

Things start going from bad to worse when Katrina tries to persuade the colony to return to the water with her and abandon Ryn. Viv and Cami (Donna's daughter) join Katrina, but Sarge, Levi, and Eliza choose to remain loyal to Ryn. After a brief confrontation, the two opposing sides call for a truce as they all decide to work together to reclaim their home. After a little while, the tank water becomes insufficient and Viv begins to undergo complications following her transformation. Katrina decides to lead them, along with Helen Hawkins, to a cave she had found when she went out alone earlier. There inside the cave, they find some cave paintings made by an ancient tribe that had once been allied with merfolk several millennia ago. After Ben finally executes the plan to stop the oil company from drilling any further, the merfolk give their gratitude to their fellow human friends. But the plan comes with a price.

After the drill was cut off by the blowtorches, the snag wire which is hooked around the drill comes off and is about to slice into Eliza and Viv, but Sarge swims in between them and ends up getting his throat slit. The other merfolk then carry him back to their home where he is given a burial. Moments afterward, Ryn goes around looking for other members of her colony, but unfortunately, many others had died, and she manages to find only three members still alive. After that, Katrina and Cami go out hunting where they find a plane wreck and find an elderly mermaid inside.

When mating season begins, both the mermaid and merman glow with an inner light. However, young have not been born in many years, due to the humans throwing pollutants in the oceans.

Due to Ian Sutton's interfere and constant digging, their allegedly mythical existence has finally been exposed to all of townsfolk of Bristol Cove, resulting in an all-out war for the survival of merpeople, humans and hybrids alike. However, it turns out that it was all a premonition.

Season Three

Coming later...

Humans who Have Encountered Merpeople

After their Existence is Allegedly Revealed in a Flashforward

After their Existence is Ultimately Revealed

Known Merfolk



Mentioned or Referenced

Physical Appearance

Mermaids possess a strange, alluring quality that many humans are drawn to which is present in both their human and aquatic forms. Warrior merman are typically seen carrying spears they use as weapons to attack and kill their enemies.

Merpeople have a noticeable sexual isomorphism in terms of their aquatic forms. While mermaids and mermen share the same scaly upper bodies, fangs, claws, webbed hands, webbed underarms, a pair of small fins right above the caudal fin, and dolphin/whale shaped caudal fins, their tails and back fins are noticeably different in appearance. Mermaids have a large, single fish-like fin running down their human backs, three long sets of webbed fins running down their tails(one along the back, and two smaller ones each positioned on the side of the tail), and a stinger growing out between the caudal fins. Mermen, on the other hand, have slightly longer tails, larger caudal fins, three or four pairs of fins shaped like those of dolphins, whales, or sharks running down their back, with an additional one positioned in the middle of the buttocks where the crack would be. Their tails also have dolphin/whale/shark-like fins along their tails in three pairs. One pair sticking out behind the thighs, one pair sticking out around the knee area, and of course a pair above the above the caudal fins similar to the females. Mermen caudal fins lack the stinger that mermaids have.


Merfolk usually only kill for survival. According to Helen Hawkins, Merfolk are highly intelligent creatures, more so than humans at least. This is displayed in Ryn's extremely quick grasp of the English language and her memory also appears to be quite superb. Merfolk have some difficulty adjusting to life on land; though given their in-exposure to human culture, this can be expected.

Because Merfolk have some difficulty speaking human languages, they tend not to speak much as they namely commune with high-pitched calls and wails. It can be assumed that they do have some kind of non-human language that they use in the ocean, as several of the merfolk have made references to stories they were told as children in the water about certain subjects.


Merfolk live in groups of colonies in various parts of the sea. These colonies are led by matriarchal leaders, according to Helen. The leader of a colony is known as the Alpha leader.

Katrina is the former Alpha leader of a colony; Ryn later replaced her as Alpha after defeating her in combat.

Ryn reveals that in other parts of the ocean, there are other colonies who are more territorial and will do whatever it takes to protect their water.

Abilities and Attributes

  • Merfolk Physiology: Merfolk have a human-like upper body and the lower body of a scaly fish's tail instead of legs. While mermaids have the upper body of a beautiful female human with flowing long hair that covers their backs, mermen have the upper body of a handsome, muscular human male. Merfolk have blue eyes which comes in varying shades. Both mermaids and mermen have dagger-like teeth and talons used for catching and tearing prey. They also have gill slits on their rib cage that enables them to breathe underwater and syntactically, digits fused together forming webbed hands, which reduce water resistance when they swim. In addition, they have a vertical tail fluke, similar to a cetacean's, used for propulsion. A barbed stinger at the end of their tail that is very sharp and piercing and is used as a weapon or for self-defense. Some Merfolk such as Levi and Sarge do not appear to have barbed stingers on their tails, suggesting that it is possibly sexually isomorphic that only the females possess them. Both sexes have grey skin that is covered with silvery-grey scales of varying hues, including the human half. Their voice boxes are a hybrid of a larynx and a syrinx at the base of their trachea. Mermen are seen with spikes on their backs.
  • Scale Manifestation: Their scaly fishtails are silvery gray and have pelvic fins on either side of their tail, which assist them as they move vertically or turn sharply in the water. A large dorsal fin runs down their backs while a much smaller one runs down the backs of their tails
  • Speed Swimming: Naturally, they are capable of swimming at great speeds in the water.
  • Enhanced Senses: Just like sea lions, whales and dolphins, they can hear sounds far off the ultrasonic frequency, giving them splitting headaches. For example, the strong hypersonic waves emitted by the oil rig has even caused death for some. They have enhanced night vision.
  • Fang Retraction and Enhanced Bite: In their true aquatic form, razor-sharp fangs appear in their mouth, with which they break steel in one bite.
  • Human Disguise: After surviving the painful transformation between tail and legs, merfolk are capable of taking their place among the humans.
  • Tuar Physiology: As converting their tails into legs, they can revert to their true forms, though just as painful to endure as their bones crack. This is only possible through contact with seawater.
  • Water Maneuverability: As well as swimming at high speeds, they are capable of maneuvering freely underwater.
  • Extraordinary Physical Strength: Merfolk are noticeably physically much stronger than humans. Ryn was able to overpower a large adult male and threw a pipe with enough force for it to pierce a wall. She was also able to lift an anchor and throw it without difficulty. Also, Katrina was able to punch through the glass window without experiencing any recoiling pain when she attacked Dale. This is due at least in part by the fact that the bones and tissues of a mermaid are incredibly dense; the very petite Ryn, who is roughly 5'4" tall, was shown to weigh well over 200 pounds despite having a thin, lean build. This enhanced density also makes merfolk extraordinarily durable and resistant to harm.
  • Enhanced Regeneration: Merfolk possess greater regenerative capabilities than humans. They heal quickly from non-fatal injuries within a short period. This gives them a very strong tolerance to the effects of alcohol, with both Ryn and Levi being shown drinking beer, wine, and liquor without showing much outward signs of intoxication.
  • Siren Song/Hypnotic Singing: Mermaids possess a strange, alluring quality that many humans are drawn to which is present in both their human and aquatic forms. They can use their voices to sing a wordless song that can manipulate a human's feelings or actions, depending on its intentions; this can range from influencing a person to defend the mermaid from others, attracting a human to them, or compelling them to stop an action (such as trying to shoot them with a tranquilizer gun, for example). This song has a negative affect on humans, creating a type of lesion on the brain beginning in the frontal lobe, the region that controls impulses and inhibitions, which can lead to side effects ranging from hallucinations, delusions, lowered inhibitions (preventing someone from doing something they want to do but know they shouldn't), and even causing some to do things they do not want to do. Some mermaids (typically healers) can also learn to use their voices to sing a sequence of tones which, when accompanied by hand gestures over a person's body, is capable of moving pain out of it.
    • According to Levi, only mermaids are capable of this power, as mermen are not able to sing. Ryn also explained that merfolk are only capable of singing the siren song when they are in the presence of a human, as when she was asked to sing into a recording device whilst Maddie and Ben waited outside, Ryn responded, "Song only comes when I sing to a human." The use of a mermaid's singing voice to remove someone's pain is described by Ryn as not being a true singing like their siren song, but more like humming, which seems to be supported by the fact that Elaine Pownall has not experienced any negative side effects as a result of hearing Ryn's voice for this purpose, whereas Chris, Decker, Ben, and Maddie all suffered neurological side effects as a result of hearing the siren song (by Donna in the former two cases and Ryn in the latter two cases).
  • Bioluminescence: When mating season approaches, both males and females emit glowing light that draws them close to each other.
  • Quick Gestation: Unlike a Human fetus, Merbabies remain in their mother's wombs for less than 9 months.
  • Extremely Long Lifespans: It's unknown exactly how long a mermaid can live but they can live much longer than humans.


  • Dehydration: Merfolk are unable to survive on land for extended periods of time. After prolonged deprivation of water, they will begin to asphyxiate, and their skin will become extremely dry and irritated. After an extensive period of dehydration, their body will begin to shut down. Merfolk are able to spend more time on the surface each time they transform to occupy land.
  • Mortality: Since Merfolk are living creatures, they can be killed by conventional means (e.g. blood loss, decapitation, starvation, suffocation, and etc.). In fact, during their transformations into human form, the pain can be so great that some may even die while transforming.
  • Ocean Water: Whilst Ryn's colony were capable of temporarily surviving on land by transforming within a tank filled with ocean water, this eventually proves to be incapable to sustain them. According to the merfolk, the water must be alive for it to properly sustain them.
  • High Stress: As displayed by Ryn, following the extraction procedure for her stem cells, her cortisol levels spiked up moments afterward, causing her to become more aggressive and stressed until the point that her predatory instincts returned. Singing the siren song has been shown to help alleviate this side-effect.
  • Water Pollution: As told by Maddie, merfolk are prone to infertility in the water due to pollutants that humans had dumped into the ocean.


Their diet consists of seafood such as fish, shrimp, clams, crab, and lobsters. In "Pilot", a shark's head was seen with bite marks indicting Merfolk eat shark as well. Ryn also killed and ate a rat when she was first on land. Though Ryn and the other merfolk initially seemed repulsed by food that wasn't fish once they took human forms, they have been shown to soon develop a taste for other human food; Ryn has been seen eating and liking a variety of fruit and side dishes and has recently professed a love for Jell-O, while Cami was seen enjoying grapes by tossing them into her mouth.

Merfolk have also been shown to enjoy alcoholic beverages while in their human forms, with Ryn often partaking in social drinking with her human friends and Levi making his fondness for beer very well known.


In the water, females and males aren’t equal; women are in the position of authority while men act as their subordinates.

When a mermaid or merman dies, their family takes their body and swim for a long time, taking the body to the deep ocean and leaving it in a special place so no other animal can find it, sort of like a funeral. Due to the matriarchal society of the merfolk, it is usually the females who do most of the activities underwater, such as hunting and are always seen eating first. When it is time for mating, males and females glow to draw potential mates in, but the females are the ones who choose with whom they mate.

The males can attract potential mates by stretching and twisting their necks and produce a kind of bio-luminescence. Then the females bite on to their male mate's necks and smack them with their tails. Ryn later states that males can even die from mating too much.

Merfolk are able to have offspring of their own, but only in clean seawater.


Season 1

Season 2

Season 3

  • Borders
  • Life and Death
  • Revelations
  • Survivor
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