|“||But the darkest consequence was something my parents never anticipated... The hunger. Blood...had made us reborn, and it was blood that we craved above all else. We could not control it...||”|
Blood is a specialized bodily fluid that both delivers nutrients and oxygen to the cells and also transports metabolic waste products away from those cells. Immortals, vampires and hybrids need to drink blood to function. If a vampire cannot feed on blood for an extended period of time, they will weaken to the point of desiccation. Blood is also what provides vampiric creatures with their supernatural abilities, such as enhanced strength, speed, agility, senses, healing, and mind control, and as a result, the strength of their abilities can be affected by starvation or extreme blood loss. Most vampires drink human blood, but there are some that choose to exclusively drink animal blood, such as Stefan Salvatore, or vampire blood, such as Mikael. However, animal blood does not provide the same level of nourishment to vampires as human blood does, which is why most vampires won't even consider it unless they have no other option.
Types of Blood
Feeding on human blood is the final phase in becoming a vampire after a human has died with a vampire's blood in their system and reawakened in transition afterward. If an individual chooses not to feed and resists human blood, the transition will not be complete and the individual will die permanently within twenty-four hours. (An example of this is Bill Forbes, who died after failing to drink blood to complete his transition in Bringing Out The Dead). However, the urge for human blood is a crucial aspect of life as a vampire— the bloodlust and hunger becomes as constant as breathing, and every individual must learn to adjust to this new lifestyle in order to maintain self-control and to avoid exposure.
When a vampire experiences moments of hunger, bloodlust, or any other heightened emotion, their vampiric aspect becomes evident in their facial changes. Their eyes become extremely bloodshot, the veins around them darken and protrude, and their fangs become exposed. The majority of vampires drink human blood. Some choose to consume blood bags from blood banks as a more ethical way to satisfy their needs, while other vampires feed off of willing or compelled individuals. There are also those who go so far as to feed on their victims until their death, though it has been proven that it is not necessary for a vampire to kill in order to feed --it is simply a skill that takes practice to achieve. Furthermore, animal blood makes a vampire considerably weaker than those who drink that of humans, though the vampire's advanced age may still give them an advantage in a fight. The latter point was demonstrated to be the case when Damon returned to Mystic Falls; he and Stefan immediately engaged in a fight in which Damon easily bested his younger brother because he had embraced his vampiric ways with open arms, while Stefan stuck to a strict animal-only diet because of the guilt he was burdened with from his past.
It has also been shown that the blood from witches and werewolves in their human form seems to have the same effect on vampires as human blood, as vampires have been seen to feed on either species with no negative physical effects.
Some vampires (such as Stefan Salvatore) choose to feed on animal blood rather than human blood. Animal blood does not provide the same level of nourishment to vampires as human blood does, and vampires who drink animal blood have decreased strength, decreases speed, decreased healing abilities and a lower tolerance to pain as compared to vampires who feed on human blood. Since it is stated that to complete a transition into a vampire, one must drink human blood, it can be presumed that feeding on animal blood will not suffice to complete the transition into a vampire. This assumption is supported by the fact that there has been no vampire on either series who has completed their transition by feeding on blood from any non-human source.
Vampire blood is necessary in the process of turning a human into a vampire. The human must have vampire blood in their system at the time of their death in order to begin the transition. However, vampire blood cannot turn a human into a vampire if the human is already dead when it is ingested, nor can it be used to heal someone from a fatal wound if they have already died.
Vampire blood also has strong regenerative properties, and when ingested by a human it will heal them of almost any wound and the majority of illnesses within seconds. It was also revealed in Grayson Gilbert's medical journal that he used vampire blood to cure Megan King of a heart condition when she was a child during his tenure in the Augustine Society. Vampire blood cannot cure cancer, however, most likely since it works by increasing the speed at which cells regenerate to heal wounds, whereas cancer cells are biologically immortal (that is to say, they don't die from old age like normal, healthy cells, and cancer cells can only be "killed" by methods such as surgery, chemotherapy, radiation, etc). As a result of the physiology of cancer, the exposure of cancer cells to vampire blood creates many problems due to their out-of-control growth.
An exhaustive list of which conditions and illnesses can and cannot be treated/cured by vampire blood is currently unknown. In Dead Man on Campus, Damon injected Wes Maxfield with extremely serious and oftentimes fatal diseases such as rabies and ebola to torture him, and he was later healed with vampire blood with no ill effects shown afterwards. However, both Enzo and Lily Salvatore have stated that they died of consumption, now known as tuberculosis, so whether it can be inferred that there are at least some pathogens that vampire blood cannot cure or whether this is just a case of retroactive continuity has yet to be determined. It has also been shown that vampire blood will have the same regenerative effects if injected directly into the blood stream rather than ingested orally, as evidenced in She's Come Undone, when Caroline Forbes injected her mother with her blood via a syringe when Liz was unable to drink it due to being unconscious, and it still fully healed her injuries. Bill Forbes was also healed with vampire blood using the same method by Dr. Meredith Fell in The Ties That Bind after he was attacked by Tyler Lockwood in his werewolf form.
Vampires can also feed off of the blood of other vampires, as demonstrated by Mikael. However, Mikael implied that it takes time and practice to learn to live on the blood of vampires. Mikael has been known as one of the most powerful vampires in history, if not the most powerful, but it is unknown whether his diet of vampire blood caused his increased ferocity, or if it was simply Mikael's personality combined with the fact that he was a thousand-year-old Original vampire that made him so formidable. Augustine vampires such as Jesse have a natural desire to feed off of vampire blood instead of human blood due to either being conditioned to crave it or by being injected with the "Ripper compound." In the case of Augustine vampires, a diet of vampire blood can actually significantly increase their physical strength, as the newborn vampire Jesse was easily able to overpower Damon Salvatore, who was over 150 years older than him. While werewolves don't require vampire blood to survive, it has been confirmed that werewolves transformed under the full moon do/can/will eat vampires, as they have evolved to hunt vampires as their main prey.
Characters who have used their blood to cure people
Although generally, witch blood contains no adverse properties that differ from human blood, it has many uses throughout the witch community. For example, blood can be used in witch-locator spells. This was demonstrated when Olivia Parker gave Elena and Damon her blood while in the prison world so she could both locate and connect with them.
Any descendant of the Bennett family who still has the ability to perform magic can use their blood to perform powerful spells that require the use of Bennett Blood. Their blood can also be used to break some powerful spells. If one Bennett witch performed a spell using their blood, another witch in the bloodline is able to break the spell using their own blood, provided they are an active witch. This was demonstrated when Abby and Bonnie Bennett unsealed Esther's magically-locked coffin to release her preserved body, as well as when Bonnie and Lucy Bennett donated their blood for use in traveling between the living world and the Prison Worlds. Many witches bind their blood to spells to ensure that they cannot be broken by any other lineage of witches or can only be accessed by said lineage. Sheila Bennett once donated her blood to help the Gemini Coven create the prison world. Due to this, Bennett blood is required to transport between the realms.. Bonnie Bennett once made Damon, Stefan and Klaus drink her blood so that it may bridge them all together. It made it possible for her to give them the power to stop Alaric's heart when she stopped Jeremy's. Bonnie's blood was used to free Damon and later Kai from the 1994 prison world.
Qetsiyah's blood is a powerful ingredient in spells, due to the immense magical power she possessed when she was alive. Bonnie used Silas' headstone, which contained a large amount of Qetsiyah's calcified blood, in order to channel the power with Qetsiyah's blood to temporarily lower the veil to the Other Side. Using Qetsiyah's blood, Bonnie was saved from having to wait until the full moon to do the spell. Qetsiyah's blood, in addition to the power from the Expression Triangle, was more than enough power to successfully complete this powerful spell. While Bonnie was trapped in the 1994 Prison World without magic, she traveled back to the island to get the Prison World's version of Silas' headstone in order to channel Qetsiyah's blood as a source of magic. With Qetsiyah's magical blood, the Ascendant, and the combination of a solar eclipse and the Aurora Borealis that resulted from the colliding Prison Worlds, Bonnie was able to portal her way back to the living world in Let Her Go.
The blood of a Mikaelson Witch can be used by others as a catalyst to replicate Esther's Immortality spell that created the Originals as seen with Freya. Presumably the blood of any living Mikaelson Witch will do, which includes Hope. Since most of the members of the Mikaelson family are currently Vampires, the only people who are alive who have Mikaelson Witch blood are Freya and Hope.
Niklaus Mikaelson's blood
Klaus is the only being in the world whose blood can cure vampire of the lethal effects of a werewolf bite. After a bitten vampire ingests Klaus' blood, he or she is immediately healed of the bite wound "as though it never happened," in Klaus' words. Additionally, Klaus is the only vampire on earth whose blood can turn a werewolf into a hybrid, assuming that he has doppelgänger blood, or the blood of his daughter, in order to complete their transition.
Hope Mikaelson's blood
Hope's blood can be used to turn werewolves into hybrids, it is also required to finish their transition afterward. It can be presumed that her blood can also cure a werewolf/hybrid bite, though it has yet to be demonstrated. In addition to these qualities, Hope's blood can also act as a potent binding agent and can be used to break complex spells cast by other witches as a result of her witch heritage.
Human doppelgänger blood was needed in the spell that transformed Mikael and his children into the Original vampires, and was also a required ingredient in the sacrifice ritual necessary to break the Hybrid Curse that was placed on Klaus Mikaelson in the early 11th century. Human doppelgänger blood was also a necessary component for Klaus, the Original hybrid, to turn other triggered werewolves into hybrids. Instead of feeding on regular human blood after awakening during the transition period like vampires have to, these hybrids instead needed feed on human doppelgänger blood. Klaus used Elena's blood to break his curse, and then continued to use it in order to sire his hybrids, including Tyler Lockwood, as he was under the impression that she was the only human doppelgänger in existence. However, after Elena was turned into a vampire, her blood could no longer be used to sire hybrids.
The blood of a doppelgänger is also a powerful source of magic for witches to use in spells due to their mystical nature, and their blood has been used on many different occasions in order to serve as a binding agent or a source of power for extremely powerful spells. The Travelers also discovered that the blood of the last two remaining doppelgängers from each bloodline (Stefan from Silas' bloodline, and Elena from Amara's bloodline) can be mixed together to be used to reverse any non-traditional form of magic. The Travelers intended on using their mixed blood to undo the curse put on their people by the witches, which would slowly undo every spell cast using a non-traditional magic source, including the spells that created the Other Side, the werewolf curse/activated lycanthropy, the spell that created the Originals (as well as every single "living" vampire descended from them) and the daylight rings that protect them.
Examples of Doppelgänger Blood Used for Magical Purposes
- Tatia's blood was used in the adapted version of the Immortality Spell that was used on the Mikaelson family (Mikael, Elijah, Finn, Klaus, Kol, and Rebekah) in order to create the Original vampires.
- Tatia's doppelgänger blood was also used to perform the Hybrid Curse, which was placed on Klaus to keep his werewolf side from manifesting after he triggered his curse shortly after his transformation into a vampire. Elena's blood was used to break this curse over 1,000 years later, as she is a descendant of Tatia and, at the time, was a human doppelgänger.
- Elena's blood was also taken later by Esther, who used her blood to bind a spell which linked all of her children together. Her plan was to cast a spell to make Finn human again, which would make the rest of the siblings human again as well. Then, she planned to kill Finn, which would result in the deaths of all of her children. This plan ultimately failed, because her connection to her source of magic (the entirety of the Bennett bloodline, living and dead) was severed by Abby Bennett Wilson's death and subsequent transformation into a vampire.
- When her first plan failed, Esther used Elena's blood again to turn Alaric Saltzman into an Enhanced Original vampire who would have superior supernatural abilities that would allow him to finally kill her children and the rest of the vampires once and for all.
- Qetsiyah used the blood of progenitor of the female doppelgänger line, Amara, as well as that of two of her shadows (Elena, Katherine, and Amara), to transfer the status of Anchor to the Other Side from Amara to Bonnie Bennett.
- Markos mixed the blood of the final two doppelgängers (Stefan and Elena) to do an experiment, by turning Sloan into a vampire. Then, he had her drink the mixed doppelgänger blood, which stripped away the vampire magic. Unfortunately for her, the blood wasn't a cure for vampirism, it just removed the vampire spell, which was created by witch (spirit) magic. As a result, Sloan was returned to her previous state before becoming a vampire, which was a human who had her throat slit by Markos. Because the magic that reanimated her body was gone, her throat re-slit itself, and Sloan died once again.
- As a result of Markos' experiment on Sloan, the Travelers learned that the curse that was placed on them could be lifted using the mixed blood of the last remaining pair of doppelgängers. This was later accomplished by the Travelers using the last of the mixed doppelgänger blood to cast the Magic Purification Spell over Mystic Falls.
Once the cure has been ingested, the blood of the human who took it, automatically becomes the cure itself. The blood retains its ability to make a vampire/immortal human. However, one weakness is that the cure can be taken from its host by draining the cure. The cure has been in four bodies so far; firstly, Katherine, Silas, Amara and Elena.
- "I had the cure you created running through my veins, and when Silas sucked it out of me, I started aging faster than normal. So basically, I'm dying, and I need you to fix me. You made the cure. Now, make something that stops the aging. Otherwise, no blood for you."
- —Katherine explains the side effect of the cure being extracted.
After Katherine was force-fed the cure by Elena, she became human (or, rather, a human Traveler) again. However, the cure remained in her blood. Silas, who desperately wanted to cure himself of his immortality so he could kill himself and reunite with his true love, Amara, in the afterlife, fed on Katherine's blood to the point where she almost died, which cured him of his immortality and returned him to his human witch identity.
Once Silas drained Katherine of nearly all of her blood, he was cured of his immortality. As a result of ingesting the cure, Silas' blood then became the cure as well. When Silas realized that Amara was still alive after she has spent a millennium desiccated and hidden as the Anchor to the Other Side, he admitted to her that he had taken the cure to die and be with her. After centuries of torment from feeling every dead supernatural's death as they passed through her to the Other Side, Amara desperately stabbed Silas in the neck with a piece of glass so she could feed on him and cure herself of her own immortality.
When Rayna was spelled by the Shamans into becoming The Huntress, the tea of protection provided her near-complete resistance to all forms of non-shamanistic magic. Her blood was also given special properties so that if a witch was to ingest her blood, it would completely suppress the witch's magic. Continued exposure to her blood (for a number of years, on a daily basis), it would eventually poison the witch, ultimately leading to their death.
- Witches can use magic to boil the blood of a being or turn their blood into acid. Neither of these acts are fatal to a vampire or hybrid; however, this would be deadly to humans, which include witches and werewolves.