Nanda Baba

Nand (also known as Nanda Gopa or Nanda Baba), according to the Harivamsha and the Puranas, was the head of the Gopas, a tribe of cowherds referred as Holy Gwals. He is popularly known as the foster-father of Krishna.
Nanda was the Chief or Mandaladhish of Gokul Mandal that was one of the most powerful branches of Yadavas.Vasudeva, took his new-born son Krishna to Nanda on the night of the child's birth so that Nanda could raise him. Nanda, who was married to Yasoda, brought up both Krishna and Balarama. Krishna derives his name Nandanandana (meaning son of Nanda) from him.
Nanda was brother of King Vasudeva.

Nanda Mythology

King Nanda

Nandagopa was the father of Goddess Durga(Yogamaya) and adopted father of Lord sri krishna. He took care of his sister Rohini's son Balrama.Nanda, also identified as King Nanda in many scriptures was a kinsman and great friend of King Vasudeva.

Krishna Legend

According to Bhagavata Purana, King Nanda of Gokul Kingdom was stepbrother of King Vasudeva.