Even if it is considered Apollos world once, he still had to pay tribute to his father, all the gods did this in their worlds. Much a like a tax system, they all have to pay a little to get the protection of a big shot.
Shrouding the temple with his authority of darkness, it served as a temporary barrier. Of course with how humans are, there are bound to be some cults formed worshiping that thunder rapist bastard and Zeus will still get his fair share of worship and faith.
Humans are just like that. Their way of thinking will always create the unexpected. Perhaps they felt that some miracle will appear.
There has been various cases around different realms and worlds. They would worship an evil god even if they knew that they had to sacrifice themselves. They would would worship a god even if they had to sacrifice their own child. Hell they would worship even a piece of shit if they have strong enough delusions.
With no other options, he orders some one to guard the temple.
With that unpleasant task, it was time to announce his presence and rule over the world.
He appeared suddenly in one of the most populated cities and using his divine power, his voice could be easily broadcasted to all the ears in the world.
"Apollo has died!!! I am your new god!!!!", he states with a tyrannical presence. When all the inhabitants of the world heard his godly voice, they were compelled to obey and listen.
Of course he simply chased Apollo away, but they would never know that.....
"I demand human sacrifices!!!!! Worship and you shall live, defy me you shall die!!!", he demands with little remorse.
In his realm, human sacrifices were nothing out of the ordinary and where conducted regularly. Usually it would be a fight to the death, after a festival, or simply gouging out ones heart on top of an alter. (Yup Aztecs and loved to preform human sacrifices)
"Human sacrifices?!?!?!? What kind of god is he? He's the devil!"
"The gods have abandoned us!!!"
"Lord Apollo save us!", many started send prayers that would fall on death ears. The god they once worshiped and revered was already gone.
Seeing the mortals despair greatly amused Tezcatlipoca. What can they even do? To him there were like whining children.
"My name is Tezcatlipoca! I'm the new sun god!!! Should you fail to uphold the quota, your world will never see day light again!!", naturally the people won't convert religions without a little bit of fear and force.
Tezcatlipoca reverted back from his sun god persona to his original god of darkness appearance. With his authority over the world, the day became night. Plunged suddenly into darkness the humans fear increased several levels. Tezcatlipoca didn't forget to assert some killing intent to further scare the living day lights out of the mortals.
Due to this godly show of power of turning day into night, Tezcatlipoca came to be know as lord or the sun in the day and lord of the moon at night. Changing the sky depending on his mood.
With this he seamlessly blended his authorities together and received worship from both the the sun and moon! Little would Tezcatlipoca come to know of this until his rule and myth solidified. He did not expect to get the best of both worlds. Not only did he not have to start from scratch, reshaping his myth and what he was associated with, he could keep his previous authority along with his new one. He became to be know as a duality god. God of the light and darkness, sun and moon, day and night.
Apollo and other gods would never be able to do this, or else they would offend their fellow pantheons and would start a war!
The mortals were frightened by his show of power, but they where hesitant about killing their fellow brothers and sister. They were taught that human sacrifices would greatly offend the gods, rather than please them.
In Greek mythology, it is forbidden to offer human sacrifices to the gods. As the myth goes, a king wanted the graces of the gods and built a grand temple of Zeus. Pleased, the gods started to favor the mortal and his nation. Then he became a full fledged, boot-licker and a religious fanatic.
With this he gave out more offerings and more worship. In return the gods started to favor him even more. Soon they decided to meet him in person and the king had the honer of hosting a feast. The crazy bastard was so obsessed he even feed the gods his own son!
"He is my most prized possession, the god will surely look a soup made of his flesh!", thought the king.
The gods found out and threw up after learning that the stew they were offered was made of human flesh! The gods weren't pleased at all and in their wrath they turned the king and all his family (with the exception of the son he sacrificed) into a wolf! The Greek gods had a taste of turning people into animals as punishment. Heck the he gods also had instances where they like to turn some people into trees as well. They sure are creative!
Fun fact, this was the origin of how the werewolves cam to be and also some of their decedents along with other monsters that Apollo took to populated his world. As expected they cursed the gods and they where also in the army that rebelled against him.
With this new ideology of sacrificing humans, it was new and terrifying for the mortals, but did Tezcatlipoca care?
This is why Greek and Aztec gods hate each other. And currently some secret society were goading both sides into a hot feuded war...
With the imposter posing as Hera whispering things to the head of the Greek pantheon and the location of Apollos world to be leaked that allowed Tezcatlipoca to invade at a crucial time, it would add more oil to the raging fire of distaste that both side had for one another. Currently it wasn't known who the mysterious god that Apollo couldn't beat was, but if revealed revealed to be an Aztec god, it would be the last trigger to cause a full scale war between the pantheons.