Ciara Houston and Carlo Parker fell in love when they both attended Sims University. Carlo and Ciara married while still in university, and Carlo graduated first, leaving Ciara behind. Ciara had many extramarital affairs when still in college, going around with Shannon Arkers, Derek Khan, Debbie Richards, and Shea Hollis. Upon graduating, she committed fully to Carlo and they soon had Ciaran. Ciaran's birth strengthened the relationship between Ciara and Carlo and they vowed to bring up their son to be a respectable member of society, with Ciara working as a successful businesswoman and Carlo the chief of the Bridgeport Fire Department. Ciaran began showing a mean streak in his childhood, often apathetic and borderline emotionless, and lacking empathy. Ciaran slacked off in school, was mean to his fellow classmates, and caused chaos. Both Carlo and Ciara were too busy with their careers to control Ciaran fully, however his relationship with both his parents was good and he didn't act out to disappoint them.
Ciaran noticed his parents relationship was starting to slip due to their schedules, so he organised them to go on a two day vacation, leaving him alone at the house. When getting the mail, he found two love letters addressed to Ciara, one from her friend Apollo Bloom and the other from her college fling Derek Khan. Ciaran became furious, convinced these men were out to destroy Carlo and Ciara's marriage, he put a plan into action. He snuck out of the house and decided to eliminate the men who wanted to steal his mother away from his father. First, he practiced what he would do on an innocent passer by named Antoinette Switzer, setting her on fire and leaving her. Overnight, he killed Apollo and Derek too. Because of his red and black attire, he was dubbed The Red and Black Assassin due to his identity still not uncovered. Despite murdering three people, Ciaran continued on as normal, glad his mother and father's relationship is now safe from men trying to woo Ciara away. In the meantime, Ciaran fell in love with Sonia Harrison, a goth girl who Ciaran saved from bullies. The two developed a strong connection and Ciaran even took Sonia to prom.
Ciaran allowed himself to forget about his three murders and continue on as normal, his family relationships were healthy, and he had his own love by his side. While his mother was out working late, his father Carlo invited his workmate Ricky Bailey over. Ciaran came home to found Carlo and Ricky in bed together. Ciaran felt betrayed, not only because his father cheated, but because he had killed two people in an attempt to keep his parents happy and protect his mother when it was really his father he needed to worry about. In a fit of rage, Ciaran set fire to the bed. Ricky died, but Carlo survived. Ciaran took Carlo and held him in the graveyard, while Ricky's remains in the burned out bedroom where mistakenly identified as Carlo's, devastating Ciara. Ciaran decided not to tell his mother the truth about Carlo's homosexual affair, instead allowing her to think he died trying to put out a fire without his uniform caused when a lamp exploded. Carlo died of starvation in captivity, and Ricky was reported missing as his remains were still thought to be Carlo's. Ciara began dating her former college flame Shea Hollis, a PlantSim who had recently been divorced and had an adopted human son from his previous marriage. Ciaran approved of the relationship, but was ready to kill if necessary.
Ciaran grew into a handsome yet slightly disturbed man. Ciaran put his murderous teenage years behind him in order to start a life with Sonia. When out in a bar, he met Morrigan Hemlock, a vampire and close friend of Ciara's, she was bored of her married life and needing an escape. Ciaran and Morrigan began an affair. Ciaran was caught between the two women, Sonia kept him grounded but Morrigan gave him a danger rush. Another thing that made him conflicted was the fact that he had killed his father for having an affair, and he was now doing the exact same thing. On the night of Ciaran's high school graduation, Shea accidentally let slip that he was in a relationship with Ciara during college, Ciaran put two and two together and realised that Ciara had been having extramarital affairs in the early years of Carlo and Ciara's marriage. Disgusted that his mother and father's marriage was based off of lies and affairs and deciding she was just as bad as Carlo, he finally snapped once again and attempted to kill Ciara, only being stopped by Shea. In his rage and betrayal, Ciaran blurted out his involvement in the murders of Apollo, Derek, Ricky, and Carlo. When pushed, he admitted he killed Antoinette as a "test subject" but her murder slipped under the radar due to her being fairly new to Bridgeport and Ciaran didn't even know her name. Ciaran also admitted that while his motive for the murders was to keep Ciara and Carlo's marriage from being under threat, he also enjoyed the killings immensely. Ciara realised her only son was a violent and dangerous person, and resolved to stop him. Before she could do anything, he had fled the house. The police searched for Ciaran, knowing him to be a dangerous person on the loose. Two days later, he was found starved in the same place he killed Carlo. Ciara was devastated at her only child's fate, yet took comfort in the fact he couldn't hurt anyone else and she still had a son in Henri, Shea's adopted son from his ex-wife.
Ciara and Shea got married soon after Ciaran's death. Ciara took the name CiCi Hollis to avoid being associated with her murderous son. At the wedding, Sonia showed up and announced that she was pregnant with Ciaran's baby. CiCi was shocked but told Sonia she would support her as much as she wanted, being the baby's grandmother. The next day, Morrigan came over to confess that she had slept with Ciaran before his death and was also pregnant with his child. Upset that her close friend would sleep with her adult son, who was already in a relationship and expecting a child, CiCi cut off Morrigan as a result.
Soon after Ciaran's death, Morrigan gave birth to a baby girl named Antonia Hemlock. Antonia's birth prompted Morrigan and CiCi to make up, but she also announced her intentions to raise the baby as her and Wogan's baby and CiCi will not have any involvement in the child's upbringing. Soon, a baby girl was dropped off at CiCi's doorstep. While CiCi initially thought Morrigan had a change of heart, Sonia came forward and confessed that she wanted nothing to do with the baby and didn't even tell her parents she was pregnant. CiCi is currently raising baby Praise Hollis (initially named Georgina by her birth mother) with Shea and they plan on raising the baby as their own daughter, while Morrigan and Wogan raise baby Antonia.
- Ciaran is similar to Samara Bain, in the case that they were both attractive young adults who tended to murder by fire. He also was similar to Karen Stradenflugen in the sense that they were both willing to murder family members in order to achieve their goals, as well as the fact that they both ended up becoming parents themselves.