He used to be a warm and cheerful God of the Dawn called TLAHUIZCALPANTECUHTLI. Then along came the Sun.
Sun God TONATIUH was a really arrogant piece of work, demanding all kinds of unreasonable sacrifices. This was even more annoying because the week before, TONATIUH had been a feeble God of Nothing and common as muck.
TLAHUIZCALPANTECUHTLI fired a stone dart to teach him a lesson. But he missed. TONATIUH fired back and got him right in the forehead. Ouch. The pain. This didn’t improve his demeanour but only made him meaner. He turned into the cold and stony ITZTLACOLIUHQUI. And that’s why Venus is cool and the dawn is cold.
Now ITZTLACOLIUHQUI is the patron of Castigation, Stone and Cold Hard Things. Like many Gods who attempt to deal out justice, he often wears a blindfold. Or perhaps it’s a bandage for his poor injured forehead.