Killed Jack Ramsey and turned him into a vampire
Transformed Gabriela Garza into a vampire
Kidnapped Livvie Locke to make her his bride
Killed Rafe in the past
Used his demonic powers to tear apart couples in Port Charles
Turned Elizabeth into a vampire
Tricked Rafe and Alison into believing they were siblings
Caleb was one of a long line of vampires from Transylvania long ago. When he was grown up, he fell in love with a beautiful woman named Olivia. She fell in love with him, but when he confided in her that he was a vampire and wanted her to become one, too, when they got married, she was mortified of him and refuse to marry him. He killed her without taking her blood when she tried to get away from him and refused to marry him. However, Caleb's obsession with the beautiful Olivia didn't go away.
Caleb also had a kinder, gentler alter ego named Michael, who was like another personality he manifested to try to suppress Caleb's evilness. Michael was acting like a priest, and living in an abandoned monastery in the woods. He was living an isolated life to keep people from learning about his evil side, Caleb. However, his isolation didn't stop him from running into another woman who was staying at a nearby cabin. He watched her out in the woods, chopping wood for a fire. He approached her and introduced himself. Her name was Dr. Eve Lambert, a doctor at General Hospital.
Eve was staying at the cabin to do some thinking about her life, and hoping her new love, Ian, would find her there. Eve befriended Michael/Caleb. Michael gave her advice about her new complicated relationship with Ian and her divorce from Kevin Collins. Meanwhile, the Caleb side of his persona had entranced and enslaved sweet nurse Gabriella Garza, ruining her relationship with boyfriend Joe and leading everyone to puzzle over her wild behavior.
Michael couldn't conceal his secret forever. Eve wandered to the monastery to see Michael one day. She saw Caleb, who scared Eve and held her hostage. Eventually, Michael became the more dominant personality and freed Eve. He told Eve that he had a twin brother named Caleb, who was sick and dangerous and needed to be locked up. Eve bought his story and worried about his safety.
Soon after, Eve invited Michael to live with her and Ian, after he married them at the monastery. Caleb destroyed the place by fire. Michael's interest in Eve got Ian's attention. He was suspicious of Michael and thought Michael was in love with Eve secretly and wouldn't admit it because he was a priest. Ian warned Michael to stay away from Eve after he learned about Caleb and how dangerous he was.
Michael found himself having a hard time keeping Caleb's personality in control, and the two personalities faced off. Caleb knew that Michael was in love with Eve, and used her to get to Michael. Michael gave Eve an amulet necklace to help protect her from Caleb's evil. He told her he wanted her to have it as a spiritual gift for a friend.
Eve soon learned that the necklace was for protection against Caleb. Eve enlisted the help of her ex-husband, Kevin Collins, to help her when Michael's actions started to worry her. With Kevin's help, they figured out that Michael and Caleb were the same person. However, by then, Caleb saw a young girl in the woods, not far from the monastery. He found her captivating as he watched her with her boyfriend, Jack.
After Jack was near death from a motorcycle crash, Caleb finished him off. Unknowingly, he made him one of the undead, but he would not be a vampire until he tasted human blood. Caleb met Livvie in an alleyway during an emotional breaking point for her. He began exerting a hypnotic, erotic influence over her, slowly convincing her to abandon her family, boyfriend, and friends, to spend the rest of her days with him. He even conjured up an image of her comatose mother to convince her that Caleb was her future. The only step left to take was waiting for Eve to give birth to her son, and kidnapping him.
Those close to Livvie were eventually clued in to what was going on. In a final battle at the hospital, Caleb played with their minds and attempted to kill them, as Lucy -- who found out she was a vampire slayer -- tried to kill him. Ultimately, on the hospital roof, the "good" side of Caleb -- Michael -- broke through after Eve pleaded with him, and summoned a bolt of lightning to destroy himself and Caleb.
Caleb's many victims breathed a sigh of relief, thinking their torment was over. They were wrong.
Each couple began experiencing feelings of doubt and insecurity, seeds that fertilized and grew each week. What they didn't realize was that Caleb had planted those seeds and was growing stronger every time they succumbed to their need to argue, to cast blame, and to throw accusations.
Livvie was in the center of the storm, because she was doing Caleb's dirty work for him by pretending to be a small child, a long-lost love, everything. She had no control over herself. Caleb then forced her to kill Lucy.
Celebrating his return to corporeal form, Caleb drew those he hated to a restaurant called Tempted, planning to destroy them all. His grand finale turned against him when he discovered Lucy's death had been faked, and Livvie had managed to break free of his enthrallment of her. She drove a stake through Caleb's heart, ending his reign of terror -- for now.