Rāhiri is a semi-mythical tūpuna of Ngāti Rāhiri Tumutumu and Ngāpuhi. Ngāpuhi is today the largest iwi (tribe) in New Zealand. His significance for Ngāpuhi is that all the chiefly lines of descent in Ngāpuhi trace descent through him. As the saying goes:
"Mehemea he uri koe no Ngāpuhi, kihai e koe i heke ia Rāhiri, he hoiho ke koe!" ("If you are Ngāpuhi and do not descend from Rāhiri, then you are a horse!")
Rāhiri lived somewhere within the period 1475-1585, based on whakapapa (genealogical) calculations. He traced descent from Kupe of the Matawhaorua canoe and Nukutawhiti of the enlarged and renamed Ngātokimatawhaorua canoe.
His first wife was Ahuaiti. From this union came the first-born son, Uenuku. Uenuku was also known as Uenuku-kuare (Uenuku who was not blessed upon birth due to the ignorance of those accompanying his mother): while still a young boy, together with his mother Ahuaiti, he was cast out by Rāhiri and it was only when he was a young man that he was reconciled with his father Rāhiri. Ahuaiti had allegedly given her visiting brothers some of Rāhiri's best fern root, contrary to his instructions to her. This was the reason for her exile. Rāhiri's second wife was Whakaruru and from this union came Kaharau who, together with Uenuku founded the military might of Ngāpuhi.