Hunahpu is one of the Hero Twins, with his brother Xbalanque, whose exploits form the central narrative of the Popol Vuh, the great K'iche' Maya book of creation preserved in a colonial-era manuscript. In the story the twins, skilled ballplayers, are summoned to the underworld Xibalba by its lords, who resent the noise of their game, and there they undergo a series of deadly trials in houses of gloom, cold, jaguars, fire and bats; by wit and self-sacrifice they defeat and outwit the death-lords, avenging their father Hun Hunahpu, and are finally raised into the sky, in the common interpretation as the sun and the moon (or Venus).
The Hero Twins are far older than the sixteenth-century Popol Vuh text: figures matching them, and scenes of the ballgame and of the twins with their blowguns, appear on Classic-period Maya painted ceramics centuries earlier, showing that the myth was a long-standing part of Maya tradition and not merely a colonial composition. Hunahpu is thus both a character of a preserved indigenous book and a deep-rooted figure of ancient Maya religion.