He was based at Motutere, but was an active warrior, leading campaigns against the Whanganui Māori of the Manganuioteao River valley to the southwest, against Te Arawa on the shores of Lake Rotorua to the north, and against Ngati Kahungunu in Hawke’s Bay.
He was also a talented orator, who is the source of several whakatauki (Māori proverbs) and forged a lasting peace between Ngāti Tūwharetoa and Te Arawa.
[2] His mother was the daughter of Te Ata-inutai of Ngāti Raukawa, through whom he was a descendant of Hoturoa, captain of the Tainui canoe.
[3] His parents had been married as part of a peace agreement which ended an attack by Te Ata-inutai on Ngāti Tūwharetoa.
He proposed that he and Tamamutu make a journey to visit his father, Po-te-heuea, at Te Pirau on Lake Roto-ngaio.
The three children sent a messenger to Tamamutu to ask him to help avenge the murder and he gathered a war party at Tokaanu, performed a haka, and then led the forces to the Manganuioteao River, where they captured a number of villages and killed the local leaders, Tū-te-houi and Tū-te-wheriko.
Then, Tū-rāhui said that the ten people just killed were not satisfactory compensation for the deaths of Tū-te-houi and Tū-te-wheriko, but he allowed Tamamutu to leave, swearing that he would attack Ngāti Tūwharetoa at a later date.
[16][17] A year later, Tū-rāhui and Tamakana later led an expedition to Taupō and killed two elderly Ngāti Tūwharetoa ariki, Te Rangi-ka-heke-i-waho and Tawiri-o-te-rangi, at Waitahanui, east of Pihanga.
Tumiromiro was pulling the new shoots out of a harakeke flax plant, a traditional form of divination, and he allowed the Whanganui to pass, predicting that they would soon meet disaster.
Tū-rāhui distributed koaro to the war party to eat, but the supplies ran out before they got to the other chief, Tamakana, who said "There is nothing but the net, there is no food here."
[22] Tū-rāhui defeated Tū-te-tawhā, Meremere, Mana-nui, and Tamamutu in single combat, knocking them unconscious, but he was killed by the left-handed warrior, Tūkino.
When Mana-nui stepped up to challenge him, Tū-rāhui had said, "who is this man with the red-feathered cloak" (kahu kura), as a result of which, the site of the battle was named Okahukura.
These men were relatives of Tamamutu and he had been warned by Werewere, son of Tūwharetoa a Turiroa, when the expedition set out, that he should not kill them.
When Werewere found out, he went to Hipa-pātua and cut the expedition's canoes free, sending them over the Huka Falls to destruction.
Ostensibly this refers to the timber of the tōtara tree, whose sapwood decays quickly while its heartwood remains solid, but Te Rangi-pātōtō realised that he was saying that Tamamutu, as principal chief should stay still, while he should advance, so he headed off to the northwest coast of Lake Rotorua and attacked the villages of Te Awahou, Weriweri, and Puhirua, quickly seizing them.
They cooked Te Roro-o-te-rangi in the oven, Umukuri, buried him on the western shore of the lake, at Motu-hinahina, and departed.
He gifted Tunohopu the clothing of a chief and gave him a huia feather to put in his hair – the traditional symbol of chieftainship.
They agreed to return his son, showered him with presents, and made a peace with the Te Arawa of Rotorua, which proved permanent.
[6][37] Tamamutu sent two men from Tangoio down to the cliffs by the sea in order to investigate whether it would be possible for the war party to pass along the beach to Mohaka.
At low tide, this is possible, but the two men did not want Tamamutu to continue and utterly destroy Te Kahu-o-te-rangi, who was related to them, so they lied, saying that the sea made the route impassable.
[40][41] Tamamutu married Hiko, a descendant of Tia, with whom he had a son, Kapawa, who succeeded him as paramount chief of Tūwharetoa.