The Hawaiian god Kāne is considered to be the procreator and the provider of life. He is associated with wai (fresh water) as well as clouds, rain, streams, and springs. Kanaloa, the Hawaiian god of the underworld, is represented by the phallic stone of the Iao Needle.
Kapawa, the king of Hawaiʻi prior to Pili, was buried here. Maui's ruler Kakaʻe, in the late 15th century, designated Iao Valley as an aliʻi burial ground. The remains were buried in secret places. In 1790, the Battle of Kepaniwai took place there, in which Kamehameha the Great defeated Kalanikūpule and the Maui army during his campaign to unify the islands. The battle was said to be so bloody that dead bodies blocked Iao Stream, and the battle site was named Kepaniwai ("the damming of the waters").