What is the name of the Aztec god of the underworld, husband of Mictecacihuatl?

The Aztec god of the underworld and husband of Mictecacihuatl is Mictlantecuhtli.

His name means “Lord of Mictlan,” the lowest and northernmost region of the Aztec underworld. Mictlan was the destination for people who died ordinary deaths, unlike those who reached other afterlives through heroic or unusual deaths.

Mictlantecuhtli and Mictecacihuatl were described as rulers of Mictlan and as complementary opposites to Ometecuhtli and Omecihuatl, associated with creation and life. Artistic depictions often show him as a skeletal or corpse-like figure, reflecting his role as lord of the dead.

A famous myth tells how Quetzalcoatl traveled to Mictlan to recover the bones of earlier humans. Mictlantecuhtli tried to stop him with a series of tests, but Quetzalcoatl escaped with the bones, which helped form later humanity. He is sometimes confused with other major Aztec gods, such as Tezcatlipoca, Quetzalcoatl, and Huitzilopochtli, but none of those is the principal ruler of Mictlan.