Delia is adopted from the orphanage as a baby by Karen and Gene York, who raise her as their daughter. When she is a toddler, they adopt Ryder, a Hellhound, as a bodyguard for her. At school, Delia is bullied by Jerome Creighton, but takes revenge on him each time, violently and/or by humiliating him.While Delia's school is on a trip to a horse stable one day, Delia causes the horses to go into a fear-fuelled frenzy. The horse she is riding throws her off and she is subsequently hospitalized with little more than bruises. While examining her, Dr. Louis Hastings removes Delia's vanishing twin embryo from her.
When psychic Jo Thueson is hired as a nanny for Delia, Delia expresses fear and anger at the sight of Jo's healing crystals. Jo eventually takes Delia to a psychic fair, where Delia's presence causes numerous psychics there distress. When Jo and her friend Noah take a kirlian photograph of Delia, the latter, realizing that the two are trying to discover her evil, becomes angry with Jo and causes the fair to burn down.Jo later meditates with Delia, and when the latter realizes what Jo is up to, she sets Ryder on her. Ryder kills Jo, and when Karen is unknowingly impregnated as a surrogate for Delia's vanishing twin, Delia senses that the unborn child is her twin and the new Antichrist; and thus she begins to silently watch over Karen over the next nine months.
Lisa Roselli is eventually hired as a new nanny for Delia, and the latter senses that Roselli is a disciple of Satan. After Karen delivers the new Antichrist, Alexander, Delia regains her sweet and innocent demeanor towards her adoptive mother, and becomes watchful and protective of Alexander.
Eventually, when Karen learns that Alexander is the Antichrist, Delia shows Alexander to Karen. Alexander apparently influences Karen into shooting herself, leaving Delia free to protect Alexander so that he can fulfill his destiny as the Antichrist. Delia attends her funeral with Gene and Alexander.
Delia originally acted playful, cheery and sweet towards Karen. But when Karen began to discover Delia's origins and fell pregnant with Alexander, Delia became more cold and quiet towards her and watched over her silently for the safety of the unborn Alexander. After Alexander was born, Delia's sweet and cheery demeanor towards her adoptive mother returned, though she would act cold and slightly angry towards Karen whenever the latter mentioned something affiliated with Christianity or Delia or Alexander's identity.
Delia behaved cheery, sweet and playful towards Gene, and he would believe her whenever she lied about her innocence in incidents.
Due to Delia's identity as the protector of the new Antichrist, she was protective towards Alexander and quietly and emotionlessly watched over him both while Karen was pregant with him, and after he was born.
Delia became angry and harsh towards Jo whenever the latter did something to anger, provoke or upset her. When Jo tried to find out who Delia was, the latter spat in her eye and had Ryder kill her.
Delia was frequently bullied by Jerome, and would retaliate, sometimes when not even provoked. She usually hit and bit him violently in retaliation, and at one point humiliated him in front of their entire class by making him wet himself on a ladder.
Due to Roselli's identity as a Satanist, Delia was more sweet towards her than she was towards most others, and would listen to Roselli when she told her to do something.
Abilities, Weaknesses and Other TraitsEditBecause of her dark and powerful aura and personality, as well as her unholy identity as the granddaughter of Satan, Delia was less violent towards others affiliated with Satan, and feared and hated holy signs and objects. Delia cried very loudly when she was baptized as a baby, she strongly tried to avoid saying Grace at dinner, and she reacted with anger, fear and swearing upon seeing a Christian pamphlet.
Delia also had a very strong and dark aura (representing her powerful, evil and violent personality), stated to be more like a Borgia's aura than a little girl's. Delia's aura was also infectious, and thus people with psychic abilities felt distress and/or exhaustion while in her presence. Delia reacted with fear at the sight of a healing crystal, and her presence caused healing crystals to turn black.
Delia could cause accident-like events to happen as well, such as fires starting and people dropping objects. She was apparently also immune to mortal ailments due to her unholy identity and Satanic lineage. When Delia was a baby, she could cause people she scratched to suffer mild infections, and when she spat in Jo's eye it appeared to partially blind her.
According to Dr. Hastings, Delia started menstruating at the age of eight, though he may have been lying. It is also shown that due to Delia's Satanic identity and/or her malevolent personality, animals such as horses and dogs greatly feared her and went into violent panic upon noticing her.
- While Damien did not become aware that he was the Antichrist until he discovered it for himself, Delia was apparently aware of her identity as the granddaughter of Satan and the protector of the new Antichrist.
- But it is probable that it is Kate Reynolds, and that Delia and Alexander were conceived as a result of Kate's night with Damien.