The traditional view is that Cook was killed for some religious reason, although what isn't always clear. One of the most fleshed out versions of this story comes from the anthropologist Marshall Solins in his book Islands of History. So in the Hawaiian religious system, Ku, the god of war and human sacrifice, rules for eight or nine months out of the year. The other months are reserved for the fertility god, Lono. The season-long festival for Lono is called Makaihiki, and during this, the Hawaiian king, who is associated with Ku, is ritually defeated. During the Makaihiki, an image of Lono tours the island, gets worshipped, and collects taxes. And at the end of the Makaihiki period, Lono is ritually defeated and returned to his native Tahiti.