Zoso, more commonly known as the Dark One, is a minor supporting character on Once Upon a Time. He was a man cursed with eternal life, but gifted with powerful magical abilities. However, these abilities are wasted as Zoso is controlled by the Duke of the Frontlands, who owns a dagger with the power to control and kill Zoso. Feeling burdened with his life, Zoso manages to manipulate an innocent Rumplestiltskin into killing him, passing his powers on to him.