Tom Riddle Senior

Tom Riddle Sr. is a Muggle who married a witch and left her when he found out she was pregnant.

The witch, Merope Gaunt, was a direct descendant of Salazar Slytherin who went against her family's wishes and married Riddle. It is likely, though not proven, that she used a love potion to make him be attracted to her. She became pregnant and soon thereafter ceased giving Riddle the potion, hoping the child would compel him to stay with her. However, Riddle left as soon as the potion wore off. The child, Tom Marvolo Riddle, was born soon after, and Merope died in childbirth. The child, who would later become Lord Voldemort, murdered his father when he was around sixteen.

When Voldemort returned, he used Tom Riddle Sr.'s bones to make the potion that ressurected him.