Nug

Nug is a Great Old One of the Cthulhu Mythos, believed to be the father of Cthulhu.

Nug is one half of the so-called Twin Blasphemies, alongside his twin sister, Yeb. Their origin is a matter of debate. Many cultists claim they were born of Shub-Niggurath, with their father being either Hastur or Yog-Sothoth. Others disagree and claim Nug and Yeb are two halves—the male aspect and female aspect—of Cxaxukluth.

Regardless, Nug is probably Cthulhu's dad, so that's interesting.