Year of birth was 1983. Given up for adoption by his birth mother, Holly Beckett, Ansem knew he was adopted and had a twin brother, Andy Gallagher. He had been approached by The Demon who told him to wait before contacting Andy. Like his twin, Ansem was able to control people's minds, but he had progressed further with his abilities than Andy and could control people without having to speak. He used his powers to commit several murders, including that of his birth mother - whom he blamed for splitting him and his brother up. When confronted by his brother and the Winchesters, he admitted to the murders and told them about meeting the demon. He then tried to kill Dean with his powers, but was shot and killed by Andy before he could do that.
Ansem was a psychic child like his twin brother Andy and also Sam thus he gained his powers through Azazel feeding him his blood. Ansem could control people's mind like his twin brother Andy but his powers were more developed allowing him to control the minds of others without speaking.