Nightblood

Nightblood 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 Franco 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 condition hereditary. However, the condition is recessive, causing it often to skip generations. 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. 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.

History
Two years after the Nuclear Apocalypse, Becca 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 humans 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. According to Titus, the people became the first Nightbloods.

Becca's tale became the origin story of the First Commander, (Pramheda[Trigedasleng]) and those with the dark blood became known as Nightbloods (Natblida[Trigedasleng]). 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 reveals that on Sanctum, nightblood is the blood of royalty, and he refers to it as the 'royal blood'.

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

 * Becca Franco, the first Commander.
 * Commanders who ruled after Becca and before Lexa and members of their Conclaves. At least four, during the time of Flamekeeper Titus.
 * Sheidheda, the Dark Commander.
 * Lexa's Conclave: Lexa, Luna, Luna's brother and six other novitiates.
 * Ontari's Conclave: Ontari, Aden and six other novitiates.
 * Clarke Griffin
 * Madi Griffin
 * Kaylee Lee
 * Faye Lee
 * Daniel Lee
 * Victor Lee
 * Russell Lightbourne
 * Simone Lightbourne
 * Josephine Lightbourne
 * Gabriel Santiago
 * Delilah Workman
 * Priya Desai
 * Ryker Desai
 * Gavin
 * Xavier
 * Rose
 * Miranda Mason
 * Marcus Kane
 * Other Sanctum Primes

Nightblood (Serum)
"Nightblood" is also used to refer to an experimental serum created by Becca. 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 a 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. They test the serum on Clarke, 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 man 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.

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.
 * 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.
 * The Flame will bond with anyone who has nightblood. 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.
 * In Sleeping Giants, Miles Shaw reveals that the spaceship called, Eligius III, had Nightbloods.
 * 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, are surprised that the people on Earth call it Nightblood.

Gallery

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