Kiti Karaka, known also as Catherine, Kate or Kitty Clark, was born on Ruapuke Island in Foveaux Strait on 12 September 1870. Her father, Arapetere Karaka (Albert Clark), nicknamed 'Chatham Islands Willy', was born in the Chathams of Moriori and Ngati Mamoe ancestry. Her mother, Mary Owen, was the daughter of John Owen, a Pakeha, and Mary Tamairaki, who was also of Moriori and Maori (Ngati Hinetewai) descent. Mary Tamairaki had been with the Maori–Moriori settlement in the Auckland Islands; after its abandonment in the 1850s, she had apparently settled in Foveaux Strait to avoid returning to slavery in the Chatham Islands.
Kiti grew up on Ruapuke, where she was baptised by the Lutheran pastor J. F. H. Wohlers; after her father's death in 1872 she lived on Stewart Island, where her mother married James Henry Wixon. When she was 15, Kiti was taken to the Chatham Islands on the schooner Omaha by the farmer–ethnologist Alexander Shand. He was acting for the Moriori elder Hirawanu Tapu, who – concerned for the survival of his people and culture – was arranging marriage partners for the remaining Moriori. As Tapu had planned, Kiti became pregnant to Riwai Te Ropiha, son of the Wairua elder Te Ropiha.
In spite of having allowed her daughter to visit the Chathams, Kiti's mother was furious at this outcome and threatened to take court action to have Kiti returned. The owner of Kaingaroa station, Thomas Ritchie, acted as mediator and wrote to her, 'All the blame is attached to the old scoundrel Tapu'. He advised her that Tapu should be forced to make over all his property to Kiti, and that Kiti and Riwai should be legally married. Kiti's mother appears to have accepted an eventual settlement (although its details are unclear) and Kiti remained on the Chathams.
Riwai Te Ropiha worked as a farmhand for Ritchie, who described him as 'a powerfully strong, healthy, active young man'. He was one of two full-blooded Moriori selected by Hirawanu Tapu as future leaders (the other being Rangitapua Horomona Rehe of Manukau). Kiti and Riwai lived for most of their married life at Wairua in the north-east of Chatham Island. They built a Maori-style meeting house there, the only one of its kind used by Moriori on the Chathams in the nineteenth century. They had nine children, of whom six survived: Ngaria, Rotia (Roger), Ruea, Meri (Mary), Joe and Riria.
The marriage ended in the early 1900s, apparently as a consequence of Riwai becoming involved with one of Kiti's sisters, Rose Clark. In an effort to establish herself independently, Kiti went to a sitting of the Native Land Court in Wellington in June 1904. She told the court that she and another Moriori woman, Ani Wi Hoeta, were the sole surviving relatives of Hirawana Tapu and his wife, Rohana (who had died in 1900 and 1902 respectively). The judge accepted their evidence and they returned to the Chathams as legal owners of 657 acres of the Moriori reserve at Te Awapatiki. In engineering this succession, Kiti believed that she was doing no more than securing the conditions agreed to at the time of her betrothal. She had also nursed Tapu through his final illness, and extracted a will naming her as his heir.
The residents of Manukau were outraged, however. Several other families were more closely related to Tapu, and they joined forces to have the succession order overturned and replaced by another which excluded Kiti and Ani. Disillusioned and bitter, Kiti left the Chathams for good shortly after this counter-claim was heard. She never again saw the children from her first marriage and they were fostered out among other Moriori families.
That same year (1906), Kiti married Te Ao Ahitana Matenga (Joseph Ashton) of Ngati Kahungunu. They lived at Greytown in Wairarapa and had one son, Joseph (Joey) Matenga Ashton, who remembered Kiti as a strong and proud woman who would say little about her past. Kiti died at Greytown on 21 January 1927 aged 56.
Kiti Karaka Riwai's battles over land shares were part of the conflict between Moriori and Maori, and among the Moriori themselves, as they strove to retain a share of their homeland. Her marriage to a man of full Moriori descent was part of the struggle of the surviving Moriori elders to ensure the continuation of their people. Along with the Solomon family of Manukau, Kiti's Riwai and Ashton descendants made up a large part of the surviving Moriori iwi in the twentieth century. Most numerous were the Preece family, progeny of Kiti's youngest daughter, Riria, and an Englishman, Charles Preece.