In the Netflix series The Umbrella Academy, Elliot is one of the 43 children born on October 1, 1989 to women who showed no previous signs of pregnancy. All of the children had extraordinary powers and were adopted by Sir Reginald Hargreeves, who turned them into a superhero team known as The Umbrella Academy.
As a child, Elliot had the power to make people believe whatever he said. He used this power to convincing people that his father was a secret agent and that his mother was an international spy. As he got older, Elliot began to use his power for more selfish reasons. He would often lie to get what he wanted or manipulate people into doing what he wanted.
This led to him becoming estranged from his family and eventually getting kicked out of the Umbrella Academy. We don't see much of Elliot in the show after that, but we do know that he continued using his powers for less than honorable purposes. In the comics (on which the show is based), it's implied that Elliot may have become a successful con artist or even a terrorist.