If you mention religion and Aztecs to some people, they will probably picture comely maidens in chains being hauled up to mountaintop altars by burly men dressed in leather. Then, if you ask someone who isn't a pervert, they'll probably tell you the Aztecs liked sacrificing people as offerings to their Gods. Particularly women and kids.
There was, however, more to Aztec religion than just gods who demanded the regular offing of children. According to experts, the Aztecs believed there were three different afterlives, one hell-like realm called Mictlan and two places which are quite nice, Tlalocan, and Tonatiuh.
So What's the Problem?
The Aztecs did not believe your fate was based on whether or not you lived a moral life. Instead, they believed that whichever of the three afterlives you got depended largely on your role in society and the manner of your death. So you could be a total shit who spent their adult life breaking into blind people's houses to move their furniture around, and depending on how you died, you could still find yourself sitting by the side of some god in the late afternoon sun, eating cheese and drinking wine with your feet in the pool.
To end up in the hellish realm of Mictlan, you had to die either from old age or from a disease (with a couple of exceptions). So, if your syphilitic Grandpa kicked the bucket, he'd be cremated along with a dog, which would serve as his guide along the dangerous, treacherous, four-year path to Mictlan.
However, to reach the decidedly nicer realm of Tlalocan, a region of abundance, eternal spring and cuddles, you'd need to be taken out either by lightning or drowning or one of the few diseases which wouldn't take you to Mictlan (pustules, dropsy or gout).
Finally, there's a celestial paradise which is ruled over by the sun god, Tonatiuh. This last afterlife is reserved for warriors or sacrifices who died in the Sun God's name, as well as women dying in childbirth (pregnant women were considered warrior-like in Aztec culture).
This is one of the good ones.
All this leaves a rather pressing question - what happened to those who don't die of old age, disease or combat, but instead expired about ten seconds after betting their mate they could jump across that chasm over there? No one is sure, but we like to think they basically hung around a waiting room until they finally decided to just tell the gods they died in a war.