Raniera Te Ahiko was born in the late eighteenth or early nineteenth century at Taumata-o-he pa near the junction of the Mangatahi Stream and the Ngaruroro River in Hawke's Bay. This pa belonged to Te Uamairangi, principal chief of Ngati Te Upokoiri, and his son Tuhoto-ariki. Raniera's parents, Te Kere of Ngati Mahuika hapu of Ngati Kahungunu and Pungarehu of Ngati Uranga, were living at the pa under Te Uamairangi's mana. The ancestral lands of Raniera's family centred on Ohiti and Lake Runanga, about a mile up the Ngaruroro from Omahu, and part of Raniera's youth was spent at Whangaitete, on an island in Lake Runanga.
Raniera's life was to be shaped by his upbringing amidst the warlike Ngati Te Upokoiri. He witnessed many battles in which they were involved, and came to know intimately their remote fastnesses in the Ruahine Range and the upper Ngaruroro River. After the battles with Ngati Kahungunu and Ngati Te Whatu-i-apiti at Mangatoetoe and with Ngati Kahungunu and Ngati Kurapare at Kirikiri-tatangi, Raniera was living with Ngati Hinepare at Te Korea on the Mangaone River near present-day Dartmoor when, sometime before 1820, Tangi-te-ruru and Te Peehi Turoa raided Hawke's Bay. The local tribes gathered at Te Rae-o-Tahumata near Omahu under the protection of the chiefs Whakato and Pakapaka, staying together until the danger had passed.
On the death of Te Uamairangi, his grandson Te Wanikau assumed his mantle as principal chief. For over 30 years Raniera's fortunes were to be intertwined with those of Te Wanikau. His intelligence and command of tribal history earned him respect and he now lived among Ngati Te Upokoiri as their historian.
In 1820 Ngati Tuwharetoa and Ngati Te Upokoiri unsuccessfully besieged Ngati Kahungunu's island pa at Te Roto-a-Tara, near Pukehou. Ngati Te Upokoiri then withdrew to inland Patea, in the upper Rangitikei region, while Raniera accompanied Te Wanikau on a visit to his relatives at Lake Rotoaira. He married Te Wanikau's sister during the stay; they were to have no children. He later married Hokepera, of Ngati Hinepare and Ngati Hikawera, with whom he had one child.
In 1823 a second expedition of Ngati Tuwharetoa and Ngati Te Upokoiri was defeated by a combined force of Nga Puhi, Ngati Te Whatu-i-apiti and Ngati Kahungunu at Te Whiti-o-Tu on the upper Waipawa River; Raniera then lived with his family at Pohokura in the mountains for a year as a refugee. Te Wanikau continued on to Taupo with Ngati Tuwharetoa, and Raniera was later taken by Te Rarotawhana to join him there.
About 1824 Ngati Te Upokoiri went to Kapiti Island to get firearms for a further expedition. They then accompanied Te Momo-a-Irawaru to Te Roto-a-Tara, where the subsequent battle saw Ngati Te Upokoiri and Ngati Raukawa suffer great loss of life. The surviving Ngati Te Upokoiri chiefs sought refuge in the eastern Ruahine with Raniera, who had remained behind. They launched reprisal raids on Poukawa and Kairakau, then journeyed to exile in Manawatu, living with the Rangitane chiefs Tiweka and Takore at Te Kuripaka. They were later joined by Te Wanikau.
Te Wanikau died in Manawatu in the early 1840s, and in February 1850 William Colenso recorded the departure of the chiefs of Heretaunga to raise his bones. Kurupo Te Moananui of Ngati Kahungunu then invited Ngati Te Upokoiri to return to Heretaunga. Raniera accepted the invitation, and asked Paora Kaiwhata, chief of Ngati Hinepare, to prepare cultivations for him at Omihi on the Ngaruroro River. He arrived back in August 1850 with his cousin Aperahama Kaipipi.
In 1851 Renata Kawepo, the successor to Te Wanikau, went to Manawatu to gather the remnants of his people. A section of them returned and established temporary quarters at Pokonao near William Colenso's mission station. They remained there for perhaps two years before joining Raniera at Omahu. The remainder of Ngati Te Upokoiri returned in two migrations, one in 1853, the other in 1861.
In 1857 Raniera joined Te Moananui and Renata Kawepo against Te Hapuku who was selling land in which they all had interests. After the defeat of Te Hapuku at Te Pakiaka, Raniera moved to Ngahape between Omahu and Crissoge station. He was to live there for the next 30 years. He gave his home at Omahu to his niece Hoana Pakapaka and her husband, Te Waata Raka-i-werohia. He also took Kawepo to inland Patea to familiarise him with the lands over which he was now chief.
During the 1860s Raniera witnessed many changes in Hawke's Bay: a flour mill was established at Paherumanihi, much land was sold to Europeans, and there was conflict with Hauhau. Most importantly, Raniera entered a highly productive and valuable period as an expert witness in the Native Land Court. He quickly adapted to the unfamiliar milieu of the court, and with each succeeding case his reputation as a historian grew. He gave evidence on the Pukehamoamoa block in 1880, and between 1884 and 1893 was a witness for Ngati Te Upokoiri and related hapu in most of the inland Patea hearings. His evidence in the various hearings of the Owhaoko, Mangaohane and Awarua blocks has left a rich and detailed documentation of Ngati Te Upokoiri tribal history.
In the Omahu case, which began in July 1889, Raniera was the principal witness when Airini Donnelly, grand-daughter of Kawepo's sister, Erena Mekemeke, and Wi Broughton, a relation of Kawepo's, contested Kawepo's legacy. At one point the court was requested to adjourn to Raniera's residence to take evidence; he was too unwell to come to court and by reason of his age and illness would 'perhaps be unable to re-enter this Court again.' In the judgement Raniera was described as 'a clear-headed witness, well acquainted with the history of this land.' Even after his death his evidence was quoted in court. Anaru Te Wanikau perhaps summed up the situation best in his evidence in the Timahanga case: Raniera, he said, had the best knowledge; his evidence was correct.
Raniera Te Ahiko died at Omahu, probably on 17 April 1894. His body was taken to Ohiti for burial. His only son, Mohi Raniera, had died in the early 1870s leaving Raniera with five grandchildren to raise. He had also gathered the grandchildren of Hinetoi, a relative who had been living among Ngati Porou since her capture at the battle of Motukumara, and brought them back from East Cape to live with him. Raniera's line continues through his two grand-daughters, Ria Mohi and Te Rohutu Mohi.