The twins were Ixbalanque and Hun-Apu. Their father was Hun Hunahpu. After Hun Hunapu was tricked and killed by the lords of Xibalba, Hun Hunapu's skull was hung in a tree. When a young virgin woman aproached the tree, the skull talked with her and then spit into her hand, in this way she became pregnant with the Hero Twins.
The stories of how the Hero Twins defeated the lords of Xibalba was taught as an example of how Maya people could also defeat demons in the afterlife.
The Hero Twins were deft players of the Mesoamerican ballgame.