Who was Fornjot's father?

Fornjot, a figure from Norse mythology, is often considered to be the personification of frost giants and is described as a primordial giant. His father is typically identified as the giant Aurgelmir (or Ymir), who is regarded as the ancestor of all giants in Norse cosmology. Aurgelmir is known for being formed from the primordial elements of ice and fire, and his body was used to create the world.