Bhishma, the son of Shaantanu and Ganga
Shaantanu married Ganga, who bore him a son Devavrata who was later known as Bhishma (the one who made the fearsome vow). Eight Vasus were born of Ganga by her husband king Shaantanu.
Bhishma, moved by the desire of doing good to his father, got him married to Satyavati who was also called Gandhakali
- Adi Parva: Sambhava Parva: Section XCV, LXVII,