|A mummified Centaur|
|Portfolio||Centaurs, Guardian the Underworld, The Dead|
|Domains||3E: Evil, Law, Death
5E: Law, Death
|Home Plane||Parallel Prime Material Plane|
An original creation of Gary Gygax for the well-regarded C1: The Hidden Shrine of Tamoachan adventure in 1979, Chitza-Atlan is an Aztec-inspired guardian of the domains of the dead. Given his symbols (and the appearance of his offspring in THSOT) he's probably a centaur.
As with many of the Aztec-inspired Greyhawk gods, not much has been written about him since that adventure, and TSR Games/WotC seems to regard them as a early mis-step that can't be retconned because Gygax.
Chitza-Atlan appeared in the Official List of Deities for Living Greyhawk back in 2005 or so, but doesn't appear in the 5e PHB List of Greyhawk deities.