Over the next few years, his reputation grew to nearby settlements, and he amassed legions of both fanatical and terrified followers. Realizing his own potential, Tenebrae then went on to enslave the village. He then went on to torture his mother for betraying the family. Tenebrae, feeding on his father’s anger, called upon the dark side to stop him, snapping his neck like a twig. The father, in his anger, attacked the boy’s mother. His father confronted his mother, who admitted to having an affair with the current ruling Sith Lord of the planet Nathema, Lord Dramath. His parent, who had no understanding of the Force grew suspicious of the boy. At the age of six, Tenebrae began to manifest signs of the Force.
The story has it he was born with eyes as black as empty space itself, and no animal would approach him. The Sith Emperor was born into a farming family and was given the name Tenebrae.
This seems to be the most logical place to start, when the current Sith Emperor was born.