Hostilities began when a chief and his priest went to get human sacrifices from a neighboring tribe for some ritual deemed necessary. Once a victim, or victims, had been killed, their families and relatives sought vengeance against the attackers. Vengeanc e could also be sought for personal slights or insults, for example, a host group being inhospitable to a visiting group. After the first killing, a cycle of retaliation continued until one of the groups sued for peace or was annihilated or driven away (Handy Native Culture 123). Peace was then restored, or alliances sealed through an exchange of human sacrifices and turtles, which were often substituted for human sacrifices (Handy Native Culture 141).

On each of the islands, traditional enmities developed. Wars were fought between the tribes of the two main political divisions on Hiva Oa, the Nuku of the Western end of the island, and the Pepane of the eastern end. The natives believe that Nuku was the elder brother, and Pepane the younger brother, who were the first settlers of their respective ends of the islands. A similar east-west division was found on Nuku Hiva: "Tei'i, traditionally the elder brother, was the ancestor of the western division, while Taipi-nui-a'aiku was the ancestor of the people of the eastern division" (Handy Native Culture 25). While the tribes of each main division on both Hiva Oa and Nuku Hiva fought among themselves, when island-wide warfare broke out, they united to battle the tribes of the other end of the islands (Handy 27-30; 31-34). Rivalries between islands also developed.

The victims slain in revenge warfare were sometimes eaten, apparently an act of revenge (Handy Native Culture 124).