Darquesse is Valkyrie Cain's True Name and another part of her personality. She is first mentioned in prophecy, apparently destined to destroy the Earth. She manifests through Valkyrie several times before being forced out after fully taking her over - and manages to gain her own body by taking over the corpse of Valkyrie's Reflection.
While the group find the Soul Catcher, Valkyrie is possessed by a Remnant in an effort to spur their messiah's coming, bringing out Darquesse. However, Darquesse is not the Remnant in control - instead, it is a part of Valkyrie which hates everything. It overpowers the Remnant possessing Valkyrie, and sets about killing the horrified Remnants with pleasure, massacring dozens before almost turning on her allies. Skulduggery arrives after a few minutes and explains that Darquesse is what Valkyrie will become if she refuses to fight back against the apathy, bitterness and hopelessness, and she finally lets go of the struggling Remnant in her body, which returns her to normal.
When Valkyrie and Melancholia are under attack by Lord Vile. Realising that only way to defeat Vile, Valkyrie forces Melancholia to try and kill her, which awakens Darquesse. Darquesse and Lord Vile engage in a huge fight, which takes them all around Dublin ,Finally stopping to fight on O'Connell Street. After a great battle, the two return to their former selves.
Darquesse is forced to emerge in order to work with Lord Vile to kill Doran, Kitana, Sean and Argeddion. She gets sent into Mevolents Dimension. Deciding to retrieve The Sceptre of the Ancients, Darquesse flys to Ratoath where China Sorrows, leader of The Resistance against Mevolent, possess the sceptre. Upon arrival, she sees Mevolent and his forces attacking the town and The Resistance. Mevolent battles Darquesse and rips off her head but she uses her magic to reattach it to her body and they continue to battle until Darquesse hits him with a horse, knocking him out. After China agrees to give her the sceptre, Serpine hits her with a blast and she hops back to her own dimension with the sceptre but she doesn't realise this. Angry, she flys back to Roarhaven and she kills Doran, Kitana and Sean but Argeddion resurrects them. He accidentally kills his alternative self and gives up. Lord Vile uses a tapping rhythm to snap back into Skulduggery and uses sigils to turn Darquesse back into Valkyrie.
Darquesse conflicts with Valkyrie's thoughts, and during a mission to rescue Fletcher, Darquesse speaks to Valkyrie, leading her into a trap. Instead of escaping, she is stuck in a large room surrounded by hundreds of Brides of Blood Tears. They shoot beams of powerful energy, and Valkyrie's leg is blown off. Darquesse remarks that she can help. Valkyrie then loses her left arm, and Darquesse tempts her again. Valkyrie loses her other arm, and Darquesse manipulates her, telling her that if Valkyrie lets Darquesse take over, there is 'no more sharing'. Valkyrie gives in to Darquesse, and she obliterates all the Brides. Fletcher and Skulduggery arrive shortly after to find a hundred dead Brides and a lot of blood with Darquesse already gone.
Darquesse is then seen next breaking through the ceiling of the Sanctuary to save China Sorrows' life. Skulduggery approaches her and she flings him aside. Darquesse places a small ball of light inside Ravel, cursing him with 23 hours of unbearable agony every day, with the pain heightening if his body gets used to it. China has the ability to kill Darquesse, but she hesitates, seeing Valkyrie's face. China then touches her, and the heat is transferred to Darquesse, who heals China. Darquesse, still wearing the clothes of a Bride of Blood Tears, ignites, and her clothes burn and her Necromancer ring is destroyed. However, she cools herself, and the shadows tighten around her, becoming like a second skin. Skulduggery attempts to negotiate with her, but Darquesse says that Valkyrie is gone, not even a little voice in her head. She says that she does not want to kill her parents, she just wants to be alive. Darquesse then flies off.
Darquesse is first seen in a state of hibernation where Billy Ray Sanguine prepares to killer her. He decides not to as he doesn't wish to upset his fiancé, Tanith. Darquesse later wakes up and decides to release the Remnants to help her become smarter and more powerful. She and Tanith attack the Soul Catcher which held them and released them. She then talks to one Remnant that had possessed a scientist, after turning him into a chair for insulting her she then decides to steal a book called the hessian grimoire as the book would hold information that could help her gain god like abilities. When attempting to steal it she ran into Skulduggery and Stephaine Edgley. The two kill Darquesse and accidentally trap Valkyrie's essence in a small Soul Catcher when the plan was to trap Darquesse, who now occupied Valkyrie's body alone. After she turns a man into a rubber duck she and Skulduggery and their friends travel to America where Darquesse fights a magic eating monster. She is then killed again so that Valkyrie can retake her body. Darquesse then possesses sorcerers with psychic powers until she kills Stephanie and possess her body. She then removes and consume Tanith's Remnant in order to get her information. She then travels to Mevolent's universe to retrieve Ravel who had been sent there to attract her. She then fights Mevolent, Vengeance and Vile but is easily defeated, forcing her to go back to her own universe. She then attacks Roarhaven to kill Ravel, after fighting and quickly destroying an army made up of Vampires, various sorcerers and the Remnants, she and Valkyrie then face off to allow three psychic sorcerers to hypnotises Darquesse into thinking she has already burned all reality causing her to travel to the universe occupied by the Faceless Ones. It's unknown if she is still alive but it is unlikely as Skulduggery said that she thought she was more powerful than she actually was due to the hallucinations.
In the prophetic vision of Darquesse, she was seen in the future destroying the world and killing her own (Valkyrie's) parents.
Powers and abilities
When in grave danger - such as being on the brink of death -, Valkyrie subconsciously allows Darquesse to take over her mind and body. As Darquesse, Valkyrie can wield a unique type of magic, possibly Ancient magic, which grants her a huge amount of strength, allowing her to break boulders, crush skulls, and punch through bones with ease. She also has the ability to fly, the ability to see and manipulate someone's consciousness. Darquesse can also dull pain and has the ability to heal even her brain and organs, making her practically invincible. Darquesse can survive injuries that would easily kill a normal mage, even one as powerful as Skulduggery. Darquesse can even withstand having her head ripped off, though she admitted there was a strong chance she'd have died had she not magically repaired herself within seven seconds. Complete destruction of the brain would kill her - however, this is almost impossible do due to her ability to heal any and all wounds magically. Darquesse has been shown to be capable of disintegrating regular humans, turning them to ash with a mere gesture. In addition, Valkyrie's normal skills, such as Necromancy and Elemental Magic are increased vastly, superior to any average sorcerer. In Death Bringer, she is shown to be capable of fighting on par with Lord Vile; however, in Kingdom of the Wicked it is shown that her power has grown greatly, as she defeats Lord Vile with moderate difficulty, and even later states that she has surpassed him. She is also shown to have the ability to see Magic, sensing its presence and nature in other beings. She can understand different people's abilities, how strong they are, and how they will use it. She can also manifest her magic in the form of telekinesis, such as using it to break Kitana's leg and moving her body towards her decapitated head.
Currently, the precise limits of Darquesse's power is unknown. As of 2012, she is roughly equal to Mevolent, if not slightly stronger - however, it has been shown that her power is increasing exponentially every time she emerges. Argeddion also states that she is learning and becoming powerful faster than he did, as she easily mastered the ability to see magic, while it took him many months. It is known that Darquesse has been prophesied to extinguish all life on Earth, and eventually the planet itself. By 2013 Darquesse has completely taken over. She could tear another mage apart with a casual flick of her wrist, destroy a thousand powerful Witches and an army of Warlocks, other mages, Wretchlings and several supercharged sorcerers. By 2014 she is sufficiently powerful to destroy a large part of Roarhaven, absorb thousands of remnants, atomize living beings and even travel to the dimension of the Faceless Ones. It was also said that, even weakened, Darquesse could defeat Lord Vile (even after he was supercharged by the Accelerator). At almost her full power, she survives a combined assault by Valkyrie (with invincibility), Melancholia, and supercharged Lord Vile, and manages to defeat all of them with a large blast of energy. However it was stated that she could not defeat more than two Faceless Ones.