Wikipedia
In the mythology of Tonga, Havea Hikuleo is the god of the world, Pulotu. The islands of Kao, Tofua, Hunga Haapai, Hunga Tonga, Late and Fonualei came from stones thrown down from the skies by Hikuleo. They are all volcanic islands. The other, (coral) islands were fished up by his brother or cousin Maui.
Hikuleo's ancestors were, according to one source, the god Pil'e ( Limu according to others) and the goddess Kele, who came from Pulotu and created the mythical land of Tongamamao for their children to dwell in. They had a son Toiukamea (hidden iron) and a daughter Māimoaalōngona (royal game of hearing) who married each other and had children. Among their children were many sons', the boy Taufulifonua and the girl Havea Lolofonua. One day they lay on the beach, naked, as they were still innocent, with their legs in the sea. The tide rose and the water covered them more and more. Then an oo (meaning: to penetrate) fish swam along and started to suck from the girl's labia, which caused her a lot of joy. Once the fish had been chased away the boy tried to gently stroke her inflicted parts but that did not give her relief. Then instead of his hand, he tried it with his penis, and suddenly the girl was consoled. So copulation was invented, and Havea Hikuleo was the first of many children.
Meanwhile, Taufulifonua and Havea Lolofonua's younger brother and sister, also twins, also married each other. They were named Fonuuta (land turtle) and Fonutahi (sea turtle) and their child was Maui (Maui Motua, that is; if he was not the child of Taufulifonua and Havea Lolofonua themselves). And the next younger brother and sister, also twins who married each other, were Velesii (small enticer) and Velelahi (big enticer), who brought forth Tangaloa (Tangaloa Eiki, that is).
When Taufulifonua had become old and close to death, he divided the universe: Tangaloa got the sky to rule, Maui the earth, and Havea Hikuleo became the lord of Pulotu.
Tangaloa's descendants would become later the (divine) Tui Tonga starting with Ahoeitu. Maui's line became the Tui Talau, while Hikuleo's offspring was Loau, and the ancestry of the Tui Haatakalaua.
The historical interpretation of this triumvirate (Hikuleo, Maui, Tangaloa) may be a struggle to liberate Tonga from the dominance of the Tui Pulotu empire in Fiji, after which the victors could divide the spoils. Or theoritically they could have been Sāmoans, which made would have made Tonga and Fiji part of the so-called Tui Manua empire. But without credible evidence or claim, it is still a mystery whether Tu'i Manu'a even existed or had power over the isles of Tonga, Fiji or any other.