Hunahpu's own story in the Popol Vuh cannot be fully understood without the generation before him: his father, Hun Hunahpu, and his uncle, Vucub Hunahpu, were themselves ballplayers summoned to Xibalba by the underworld lords, tricked and defeated there, and killed, with Hun Hunahpu's severed head hung up in the branches of a calabash tree, where it miraculously transformed into a gourd-like fruit indistinguishable from the tree's others.
When a young woman of the underworld named Xquic, daughter of one of the Xibalba lords, comes to the tree out of curiosity and reaches for the fruit, the head spits into her outstretched hand, and through this act alone, without ordinary conception, she becomes pregnant with Hunahpu and his twin brother Xbalanque. Driven out of the underworld once her pregnancy becomes known, Xquic travels to the surface world and is eventually taken in by her dead husband's mother, and the twins are born and raised on earth, initially treated poorly by their grandmother and older half-brothers before their prodigious skills, especially at the ballgame that had doomed their father, begin to reveal their true nature. The whole cycle, the father's death, the miraculous conception from a severed head, and the sons' eventual triumph over the same underworld lords who killed their father, gives Hunahpu's own trials in Xibalba the weight of a generational reckoning as well as a personal test, since in defeating the lords of death he and his brother are avenging a father neither of them ever knew, completing a debt opened a full generation earlier.