Itzamna is the chief deity in the Mayan pantheon, being the lord of medicine and was worshiped as the moon deity and the bringer of civilization. His appearance was a toothless old man with sunken cheeks and a very prominent nose. Despite his appearance, he was a very powerful and benevolent deity.
Being the lord of medicine, Itzamna was able to banish fatal illnesses and raise the dead. His cult was very popular with the death obsessed Mayans, whom were presented with the gifts of drawings, writing and the order of religious ceremonies. He also instructed the Mayans with the concept of land ownership, which was reflected in the Mayan culture. A unique feature of this cult was that this deity was not responsible for any catastrophes - being completely benign, making the fields fertile, along with ensuring an adequate supply of water for the Mayans.
It was possible he was fathered by the sun deity, since Itzamna acted as an all-sustainer in Mayan creation myths and intervened whenever it was necessary, which was a great contrast to the behavior of Hunab Ku, another, much more aloof, creator deity.
"Origin: Mexico. He is the son of the supreme Mayan deity. As the avatar of the sun god, he is the ruler of heaven, day, and night. He is praised as a hero for introducing writing, religion, and land division to the people."
—Shin Megami Tensei A-Mode DDS Dictionary
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"With a body that glimmers like the sun, this demon is a sight to behold."