Ngā-kahu-whero was a descendant of the great Te Rarawa leader Te Rēinga, whose dwelling place was north Hokianga. Te Rēinga had supreme authority over the people and land of the area and this was handed down to his son, Te Kurī. Te Kurī had a daughter, Te Ruapounamu, who had mana over land in the Waihou area, on the northern shores of the Hokianga Harbour. She married the warrior chief Tarutaru, who had mana over the land at Waireia. Their son, Kahi, inherited the mana of both parents. He married Kaimanu, daughter of Ngono, who had mana over the land at Pūpūwai. Ngā-kahu-whero was the daughter of Kahi and Kaimanu; she inherited all their mana, which gave her supreme authority in the area. She was also a descendant of the great woman Waimirirangi, who had a son, Tamatea, and a daughter, Pare. Pare married Te Rēinga.
Ngā-kahu-whero, also known as Herepaenga, was born at Waihou, in the late eighteenth century. Little is known of her childhood days. In her adult years she married Muriwhenua, who was also a descendant of Te Rēinga. Just before Ngā-kahu-whero was to have their first child, she went north to Whāngāpē, accompanied by Muriwhenua, so she could give birth among her older relatives who lived there. A son named Ngāniho Te Tai was born. Soon after, they returned to Hokianga, and eventually to Waihou. There, at Te Riha, Ngā-kahu-whero and Muriwhenua raised Te Tai and two other children, a son, Te Hira, and a daughter, Wharo. It was also in this area that they had their gardens and plantations, where they planted kumara, taro, yams, potatoes, corn, pumpkin, melons, and peach trees.
With her inherited mana over the land and the people, Ngā-kahu-whero had the authority to establish land boundaries and to give land to people, as she did to Mariao and many others. She was entitled to a share of the proceeds from sales of land made by others of the area, as when Kaumātua sold land to Bishop J. B. F. Pompallier. In all these matters no one disputed her rights. She also exercised ownership over the trees that grew on the land. Only with her permission could people fell trees in her area of Waihou; she would receive the royalties, which she kept for herself or shared with those Māori who felled the trees.
A compassionate leader of her people, she was often a refuge for those in danger of death or banishment. Kaumātua was one of those spared by her and she found a purpose for him: 'Let him light the fires to provide for those who come ashore from fishing.' She joined her people in all their activities. She went with them into battle at Waitukupūhau and Te Oneroa-a-Tōhē (now known as Ninety Mile Beach). She was with her people at Motukauri when Moetara and Ngāti Korokoro attacked their pā in May 1833. It is said that Ngā-kahu-whero threw her cloak over Moetara to prevent him from drawing his club for combat. Three years later Mohi Tāwhai of Te Māhurehure established peace between the two people: Ngāti Korokoro were to remain on the south side of Hokianga Harbour; Ngāti Manawa and Te Rarawa would keep on the north side.
It is not known when Ngā-kahu-whero died; she was buried at Papanui on Pukekōwhai, together with other descendants of Te Rēinga. She is held in great esteem as the matriarch of her people, Ngāti Te Rēinga and Te Rarawa, who treasure her memory.