Dusk is an enigmatic and powerful Vampire. Loyalty is not one of his strong points, as Vengeous was not surprised when he did not attempt to free him from prison, thus he does not take it upon himself to punish Dusk. Like all vampires, Dusk is eerily elegant and graceful. Valkyrie Cain describes him as "beautiful but inhuman." He possesses immense physical strength, superhuman agility and speed. He curbs his Vampire nature through the use of a syringe containing a chemical mixture of hemlock and wolfsbane. He has a history of holding vendettas and never stops until he spills blood.
Dusk is described as roughly 30, and good looking with the exception of his facial scar, which he received in Playing with Fire. After he forgets to take an injection, he ends up transforming. Valkyrie is able to cut him across the face with Billy-Ray Sanguine's straight razor to defend herself. He is about 6 feet and noticeably slender, with graceful movements inherent to all Vampires. With pale skin and black hair, combined with the black clothing he generally wears, Dusk's appearance is that of the stereotypical vampire, in drastic contrast to the monster he becomes when the sun sets.
In Playing With Fire, Dusk works for Baron Vengeous along with Billy-Ray Sanguine. Dusk first appears talking to Vengeous in a alley discussing how to get to Valkyrie. He later appears attacking Valkyrie's reflection with his two minions. Skulduggery arrives just in time to save Valkyrie from Dusk. When Skulduggery and Valkyrie manage to get a syringe, Dusk replies "I have plenty more." Dusk and his minions leave moments after.
While he was chasing Valkyrie, she knocked his syringe from him when he was about to inject himself with it. He loses control and transforms into his monstrous form, after which Valkyrie cut open his face with Billy-Ray Sanguine's razor, from which a wound will permanently scar.
Dusk dedicated himself to punishing Valkyrie for this, and later cornered her with his minions, The Infected. As he was transforming half way, Valkyrie stabbed him in the leg with his syringe which he had dropped, leaving him trapped between human and vampire. However, Dusk caught up with Valkyrie, telling her he was going to turn her into a vampire and set her loose on her parents in her bloodlust. However, moments later, Springheeled Jack appears and the two of them fight savagely, and Jack narrowly defeated him and threw him into the sea, which knocked him unconscious due to his weakness to salt water. He was later taken into custody by Mr. Bliss.
At Croke Park Stadium, Dusk, along with Springheeled Jack, attacks Valkyrie, Skulduggery, Fletcher, Shudder, Guild and Ghastly with guns. After he is teleported by Fletcher, Dusk defeats him and returns with Fletcher, who is unconsciousness. He then bites Valkyrie. Caelan arrives to save Valkyrie, but she is already bitten. Caelan bravely tries to fight off Dusk, but Dusk - being older, stronger, faster and far more experienced in combat than his opponent - easily beats him. Dusk then tells Springheeled Jack that he was planning on killing Jack too before running away before the bomb went off, and he proceeds to kicking Jack out of the elevator to be arrested by the sanctuary later. According to Sanguine, the reasons Dusk didn't kill Valkyrie was that it "would be much more fun to keep her alive", and because when he had fed on her blood, it had tasted "special". It is later revealed that it was not due to Valkyrie being descended from the Last of the Ancients.
Tanith convinces Dusk to join her group to destroy the God-Killers in return for telling him who turned him into a vampire. In a museum towards the end of the book, Dusk has a conversation with a vampire named Isara, discussing Caelan's death. The vampire who Caelan killed was named Hrishi, Dusk's supposed only friend. Tanith then says at the end of the book that the survivors will get their promised reward and tells Dusk that the vampire who turned him was Moloch.
Dusk briefly appears to exact his revenge on Moloch. He does this at the Battle of the Keep, where Moloch was about to release his vampires on General Mantis' army. However, Dusk decapitated him and Valkyrie discovers Moloch's corpse. As Dusk broke the vampire code, he refuses to help Valkyrie open the cage to unleash the vampires as they will kill him. He leaves, letting her know that he knows 'something that even she does not know, and he will tell her, but not tonight'.
Dusk makes a late appearance in the book with several other exiled vampires. They seek refuge in Roarhaven, which is why Dusk came to see China Sorrows in the first place. He makes the deal more attractive by saying that not only will Roarhaven be the first sorcerer city, it will be the first to count vampires as its citizens. He also offers their help in defeating Darquesse, despite not being nearly as strong during the day. China accepts their request, and talks things over. He may have been among the vampires killed by Darquesse.
Dusk is aged around 30. He's about 6 foot, slender, graceful. Good-looking (apart from the scar). He has all the usual vampire things like pale skin, black hair, and he wears black clothes.
Dusk is a very reserved and calm person, with a sophisticated manner and an almost subtle personality. He is also shown to have a particularly keen sense of honour, and has never broken the code up until The Last Stand of Dead Men. He is shown to have been tempted to do so by personal opinions and provocations, but has always relented. That being said, he is shown to be increasingly dark: his manner changes completely when Tanith reveals Moloch killed him to turn him into a Vampire - Dusk had followed Moloch his entire afterlife, seeing him as a saviour. This drives Dusk to finally break the code and kill Moloch.
Dusk is an extremely powerful Vampire, and has lived for centuries. Though he doesn't look it, he possesses incredible strength to superhuman levels, has lightning reflexes and immense levels of durability, even for a Vampire. He is also an exceptionally skilled warrior, and has held his own against opponents like Valkyrie Cain, Springheeled Jack, Caelan and even Skulduggery Pleasant himself.