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The 100 Wiki

The blood of the first Commander Bekka Pramheda is your blood.
Gaia to Madi [src]

Nightblood, originally called Black Blood, is a genetic trait that makes people resistant to radiation and is expressed through black blood. Nightblood did not occur naturally but rather is a result of genetic engineering. Becca Franko created the Nightblood serum for the Eligius Corporation to increase people's resistance to radiation. The serum was successful but had an additional consequence of making the subject's blood become black.

The serum genetically altered the subject, making the gene therapy hereditary. However, the genetic enhancement is recessive, causing it often to skip generations.[1] Nightblood is important in both Grounder and Sanctum culture and the few who inherit the trait are treated as special or royals.

Grounders call people with black blood "Natblida", which is Trigedasleng for "Nightblood". Only Nightbloods can become Commanders as they are the only ones compatible with the Flame. They also call the trait Sheidjus.[2] Sky People adopted the English-version of the Grounder term and call those with black blood "Nightbloods".

In Sanctum, it is considered Royal Blood. Those born with Nightblood are called "Hosts" or "Black Bloods", while those who do not carry the gene are being derogatively known as the "Nulls". Hosts are essentials to the survival of the Primes as they are the only ones compatible with the implants housing their consciousness.

It is revealed that August was the one who came up with the name "Nightblood." Becca and the Primes are surprised by this name, calling it Black Blood or just referring to it as the Blood Alteration or Radiation Immunity in Becca's case. If Becca had a specific name for Nightblood, she never mentioned it.


Two years after the Nuclear Apocalypse, Becca Franko injected herself with a black substance, i.e. Nightblood serum, that genetically modified her blood, turning it black. This modification allowed her to metabolize radiation at a much higher rate, including the radiation emitted by A.L.I.E. 2.0, solar radiation, and remaining nuclear radiation on Earth. Afterwards, Becca implanted A.L.I.E. 2.0 into her neck. When Becca returned to Earth, she saw the Second Dawn members in hazmat suits in the distance and told them that she was there to help, and brought a case full of Nightblood serum in tow. After Becca's death turned her into a martyr, Callie Cadogan, half of the kids in the Second Dawn Bunker and some of their parents subsequently injected themselves with Nightblood to leave the bunker and save what was left of the human race on Earth, taking with them enough serum for 2,000 more people.

Thirteen 067

Mural of Becca in the temple in Polis

Becca's tale became the origin story of the First Commander (Pramheda[Trigedasleng]) in Grounder culture. Those with the dark blood became known as Nightbloods (Natblida[Trigedasleng]), with Callie's group of Second Dawn defectors being the "First Natblidas". The majority of Grounders have normal colored blood, but may be carriers for the dark blood since Nightblood children can be born to non-Nightblood parents. Whoever is the current bearer of A.L.I.E. 2.0 becomes known as the Commander (Heda in Trigedasleng).

While Grounders lost most of the knowledge on what the dark blood does, in the fourth season, Abigail Griffin discovers that its sole purpose is to metabolize radiation. She notices this when Luna, a Nightblood, was able to fully recover from Acute Radiation Syndrome (ARS) without any medicine, while non-Nightblood Grounders died from it.

Throughout the Series[]

In Stealing Fire, after Commander Lexa is accidentally killed by Titus, Ontari slaughters the other Nightbloods in Polis in their sleep before the Conclave, and presents their heads in the throne room to declare her victory.

In Perverse Instantiation (Part 2), Clarke, with Abby's help, utilized an exchange transfusion, similar to the ones done at Mount Weather, to replace her blood with Ontari's. This transfusion allowed Clarke to temporarily become a Nightblood and accept the Flame. However, it was only successful so long as Ontari's blood continued to circulate through Clarke's body, requiring Abby to open Ontari's chest so that Murphy could manually pump her heart and keep it beating when Clarke's condition deteriorated.

During the fourth season, after her Nightblood made Luna immune to the radiation of the second apocalypse, an attempt was made to recreate Nightblood to survive the coming death wave. Eventually, Clarke was given Nightblood via a bone marrow transplant from Luna, but due to Abby's fears for her daughter, the Nightblood went untested. In The Chosen, Clarke was exposed to radiation and later became sick, but it was theorized from Luna's experience that it may take a few days for the Nightblood resistance to kick in. In Praimfaya, Clarke's Nightblood succeeds in saving her from the death wave with a young Nightblood named Madi surviving as well.

In The Children of Gabriel, Russell Lightbourne reveals that on Sanctum, Nightblood is the blood of royalty, and he refers to it as the 'royal blood'. In Matryoshka, he reveals that like the people from Earth, the Primes tried to replicate Nightblood using bone marrow transplants around a hundred years before the people of Earth arrive. However, they were unsuccessful.

In False Gods, Raven states that the crew of Eligius III knew that protective suits wouldn't work against gamma radiation which is why they had Nightblood instead.

In Anaconda, in a flashback, Callie Cadogan tells Becca that her friend August named the serum Nightblood and she has gotten many of her friends and their parents onboard with taking Nightblood and leaving the bunker. Callie and her followers later depart, taking enough Nightblood with them to save 2,000 more people.


Main article: Conclave

The Conclave is a Grounder tradition held upon the death of the Commander during which a Nightblood is selected to become the new Commander. The Flamekeeper (or Fleimkepa in Trigedasleng) uses scouts to find Nightbloods. The Nightbloods are trained to fight, after which they fight to the death. The victorious Nightblood undergoes the Ascension Ceremony after which they become the new Commander. The Flame from the old Commander is implanted into the neck of its new successor, and with it, the new Commander is endowed with the spirits of all the past Commanders.

Notable Nightbloods[]

Nightblood (Serum)[]

Anti-Radiation vaccine2

Nightblood serum

The "Black Blood" (later named "Nightblood" by August) is also used to refer to an experimental serum created by neurosciencist Becca Franko. According to the records, she first developed it for the Eligius Mining Company to protect against solar radiation for long duration space missions. She later used the serum to help the human body not reject the A.L.I.E. 2.0, protecting the body against radiation emitted from the device. In addition, it also helps the human body metabolize nuclear radiation. Becca made the cells combine by experimenting in space with perfluorochemicals and oxygenators, the building block of artificial blood. Since this chemical reaction can only happen in zero gravity, a spacewalk is usually required.

With the second Praimfaya approaching, Abby and Raven work together in Becca's lab to recreate the Nightblood serum. In "The Other Side", Raven volunteers to perform the required spacewalk to complete the serum. However, Abby instead comes up with a plan to use Luna's bone marrow instead. Clarke tests the serum on herself, turning her into a Nightblood.

In "The Old Man and the Anomaly", Abby successfully replicates the serum aboard Eligius IV in an effort to save Marcus Kane. Raven reluctantly helps her by performing the needed spacewalk. The new serum turns a young Sanctum Guard named Gavin into a Nightblood to become the host for Marcus Kane. However, the new serum is floated along with Kane in "What You Take With You" to prevent its use again. Raven states that Abby used up all of the polymer on the ship needed to make the serum and while the Primes might have more on Sanctum, they would need a willing pilot which they don't have. In "Matryoshka", Murphy suggests using a bone marrow transplant to replicate Nightblood again which the Primes had tried and failed about a hundred years before. Abby states that they failed because they didn't know the formula and Russell gives them a day to do it. In "Ashes to Ashes", Abby succeeds and Echo is transformed into a Nightblood by Ryker Desai. In "Adjustment Protocol", Abby, John Murphy, Emori, Sierra, Jade and Bryson become Nightbloods through Madi and Abby's bone marrow after Abby injects herself to protect Madi.

In Anaconda, in a flashback, Becca gives Nightblood to Tristan, a young Second Dawn cultist who has been exposed to lethal levels of radiation. The serum allows him to quickly recover from the radiation, but Bill Cadogan rejects it in favor of going to another world through the Temporal Anomaly. Callie Cadogan, August and many other cultists later take the serum in order to leave the bunker and save what is left of the human race on Earth. Before leaving, Callie injects her brother Reese and states that they have enough serum left to give Nightblood to 2,000 more people.

Notes and Trivia[]

  • Past Commanders are honored on Ascension Day.
  • The Flame is passed from Commander to Commander. When a Commander dies, the Flamekeeper takes the Flame from the dead regent and guards it until the Conclave is over and the next Commander has been revealed.[3]
    • If the Commander dies in battle, the Flamekeeper or one of their scouts would have been tasked with finding the Commander's body and retrieving the Flame.[4]
    • The Flame will bond with anyone who has Nightblood. [5] Anyone who doesn't have Nightblood and comes into contact with the Flame will die.
  • If a Nightblood flees or refuses to participate in the Conclave, they are considered cowards and traitors to the blood and are typically hunted down. As was in the case of Luna.
  • Nightbloods were first revealed in "Watch the Thrones". Following Clarke's failed assassination of Nia, Nia drips Ontari's blood onto Clarke's face explaining that Ontari will become the next Commander. When Clarke asks Lexa about the Nightblood, she explains it is the blood of the Commanders.
  • Becca first developed Nightblood for the Eligius Corporation for them to use on prisoners and colonists who were spending prolonged periods of time in space and needed protection from radiation.
  • The Nightblood resistance does not kick in right away as seen with Luna and Clarke Griffin. Both got sick for a few days after being exposed to radiation before their Nightblood cured them. Clarke originally thought that her Nightblood had failed before Bellamy Blake pointed out the time delay with Luna's resistance.
  • Some people on Sanctum, such as Josephine Lightbourne, are surprised that the people on Earth call humans with black blood, "Nightblood".
  • For the Mind Drives, it appears that both the original and the new host have to be Nightbloods for the technology to work as Josephine Lightbourne stated in "Memento Mori" that Abby she makes Kane a Nightblood and then downloads his mind.
  • There may be a limit to what Nightblood can do to protect against radiation. In "False Gods," while sending Clarke, Murphy and Emori into a high-radiation environment, Raven states that "Nightblood is not a guarantee but it will help."
    • Murphy and Emori both suffered negative effects from their exposure but survived when Hatch and the Eligius prisoners helping them didn't. Raven stated that a decontamination shower and Nightblood's metabolizing radiation would ensure that they would survive the exposure.
    • Raven states that if the reactor melts down, not even Nightblood will save Murphy. Though this is different to Clarke surviving the Second Nuclear Apocalypse due to her Nightblood, Murphy and by extension all of the Nightbloods on Sanctum would be immediately exposed to massive amounts of direct radiation at once while Nightblood had allowed Clarke to survive the increased planetary levels of radiation the apocalypse had caused rather than being directly exposed to the meltdowns.
  • In "Welcome to Bardo," Murphy is shown to recover faster than Emori from heavy radiation exposure despite both being Nightbloods. Eric Jackson states that "recovery from radiation exposure doesn't always progress in a straight line" and Emori will be fine given enough time.
  • The serum takes only a short time to work: in "Adjustment Protocol," Abby becomes a Nightblood in a very short time to continue giving bone marrow transplants to recreate Nightblood for Russell Lightbourne. In "Anaconda," after injecting her brother with the serum, Callie Cadogan states that he will be a Nightblood in just an hour.
  • Nightblood's original name if it was given one is unknown. Becca simply referred to it as "the blood alteration" in conversation as seen in "Anaconda." The Eligius prisoners and Miles Shaw also appeared to know it simply as a blood alteration with both Hatch and Nikki commenting about Murphy having "that blood alteration."
  • In "The Last War," its revealed that only Nightbloods can give blood transfusions to other Nightbloods. As a result, Jackson rejects Raven Reyes' offer of giving blood to Emori when she needs it.