I wanted to give my Modern Teenage Superhero version of Quetzalcoatl character a rogues gallery aside from his obvious arch nemesis Tezcatlipoca so I spent time looking through a list of Aztec gods to find ones that had beef with Quetzalcoatl.
Coyoxauhqui was one of the 400 children of Coatlicue the Earth Mother Goddess and leader of her sibling. One day their mother Coatlicue became impregnated by a ball of feathers, and feeling embarrassed and repulsed by such a weird miraculous way of getting impregnated, she rallied her brothers and sisters to murder their mother. She managed to cut off her mother's head...only for it to be replaced with Two Giant Serpents growing from her neck stump. She then gave birth to the twins Quetzalcoatl and Xolotl, and later gave birth to the Warrior God Huitzilopochtli as a full grown armored man wielding the Turquoise Fire Serpent Xiuhcoatl as a club who proceeded to tear all 400 of his siblings limb from limb and decapitating them throwing their heads into the sky and turning them into the Moon and stars, though while dismembered they are not dead yet and continue their war against all creation trying to consume the sun and then the earth for all eternity.
I feel like Coyoxauhqui would not care about adapting to modern times, but she also doesn't care about tradition either since she is planning on destroy everything anyway, and she doesn't want to get too attached anyone or anything, but I gave her a sport's bra which wouldn't have existed in authentic Aztec culture, cause I she is usually depicted with exposed breasts. She is mainly the Nemesis to Huitzilopochtli but she also hates Quetzalcoatl and Quetz certainly does not want her to destroy the world.
Tonatiuh was the former ruling god of the 5th Sun before being given the boot.
Originally he was a complete nobody in terms of gods called Nanahuatl, who's name meant "Full of Sores" a relatively weak and pathetic god who didn't have a divine domain of his own, but he was humble. A challenge was held among the gods to decide who would be the god of the 5th sun since Suns 1-4 were destroyed, (Mostly due to Godly infighting mainly caused by Tezcatlipoca) Nanahuatl was competing against Tecciztecatl the son of the storm God Tlaloc who was Strong, Handsome, and Proud, who was seen as the obvious choice to win, but neither of those traits were of use to him in the challenge they were presented; The two boys had to leap right into a pit of fire! Tecciztecatl hesitated cause he had a lot to lose, but Nanahuatl did not hesitate for a moment cause he had nothing to lose and everything to gain. Not wanting to be shown up, Tecciztecatl leaped in second but it was already too late and he got badly burnt in the fire losing much of his strength and his beauty but was given a consolation prize of becoming the God of the Moon. On the other hand, the identity of Nanahuatl was burned away and reborn as the radiant and beautiful Tonatiuh "He Who Goes Forth Shining"
Tonatiuh however was no longer the humble Nanahuatl. With the power to rule over everything as God of the Sun, he almost immediately became a tyrant, holding the world hostage by refusing to move the sun unless he had mass amounts of sacrifices from Mortals and Gods alike. While under his rule he hoarded luxuries like Music and Cocoa beans for himself in his Sun Palace so nobody else could have any, until Quetzalcoatl snuck inside on a gust of wind and much like a Mexican Prometheus stole Cocoa Beans and Music to share and allow to be freely enjoyed by everyone!
Later the Warrior God Huitzilopochtli got fed up with Tonatiuh's lack of action until his absurd sacrifice quota was met while the Gods of Night gradually surround the Sun to destroy it, so he defeated Tonatiuh and took over the mantle of God of the 5th Sun only demanding a necessary amount sacrifices to keep up his strength and keep the sun moving. Now Tonatiuh is essentially back to being a God of Nothing clinging to dark embers of his former power, with a lust for power and blood.
Itztlacoliuhqui "Curved Obsidian Blade" is the Aztec God of Ice, Frost, Winter, Blind Justice, Harshness, Punishment, Human Misery, and Lifeless Matter. He used to be Tlahuizcalpantecuhtli the Lord of the Dawn and a God who served directly under Quetzalcoatl though even as Tlahuizcalpatecuhtli he was not a particularly friendly god known for firing arrows at mortals in the morning. Under the rule of Tonatiuh, he became fed up with the mass sacrifices demanded of all the gods and decided to take a stand against the young tyrant god shooting an Arrow at him thinking it would teach him a lesson, but Tonatiuh caught the and shot it back piercing him through the skull and transforming him into Itztlacoliuhqui who falls from the domain of Quetzalcoatl, into the service of Tezcatlipoca.
Itzpapalotl "The Obsidian Butterfly" is the fierce terrifying warrior goddess of Death, Queen of the skeletal star demons called the Tzitzimitl and rules over the paradise world of Tamoanchan where she protects the souls of children who died too young, despite being a scary war goddess she is also fiercely maternal making her even more dangerous when those she loves and protects are threatened. According to one story she had the goddess Mayahuel, goddess of the Maguey plant, trapped in her domain. Quetzalcoatl showed up to rescue and escape with Mayahuel and they ran off together. Enraged, Itzpapalotl sent the Tzitzimitl to find and destroy Mayahuel. Mayahuel used her powers to disguise herself as a plant but one of the Tzitzimitl recognized her and lead the others to tear her apart in plant form and killed her. Quetzalcoatl found what they did to her body and with righteous fury crated a hurricane that swirled the stars.
It's unfortunate, I feel like Quetzalcoatl and Itzpapalotl could bond over their love of the people they protect if they were not at odds with each other. She has not changed her outfit to adapt with the modern era because she believes her look is Iconic and wants to be recognizable as something terrifying and brutal to strike fear into anyone who crosses her.
Mictlantecuhtli The Lord of the Land of the Dead who dwells in the lowest darkest layer of the Aztec Underworld Mictlan. In the Aztec afterlife, your fate is determined not by how you lived but by how you died;
If you were a Sacrifice, a Warrior who died in battle, or a Woman who died in Childbirth, then you would be rewarded by being reborn as one of Huitzilopochtli Sacred Hummingbirds
If you died in a way related to water, then you would be sent to Tlalocan the eternal spring paradise world of the rain god Tlaloc.
Most people who die of old age end up in the world of Mictlan, a nine layered realm where souls are expected to make a dangerous 4 year spiritual journey through all of the layers with obstacles and dangers all along the way like Mountains that crash into each other and smash anything between them, Wind that blow flesh cleaving knives, and rivers of blood with dangerous wild animals, but the trek is worth it to get to the Land of eternal rest where the dead lay down their old bones returning them to Mictlantecutli and their soul renters the cycle to come back later as someone new. It's also not entirely a bad realm, there are parts of Mictlan that are very livable and you can find Xolotl a guide of the dead who leads souls through the safest passages in Mictlan to their final resting place.
In the Aztec Creation Myth, the Gods grew exhausted from having to make new life to inhabit the world every time Tezcatlipoca destroyed it, so Quetzalcoatl and Xolotl traveled together into Mictlan to claim the Bones of the Past Inhabitants of the earth: Giants, Monkeys, Birds, and Fish, then use them as a foundation to create Humans. Mictlatecuhtli however did not want to give up the bones, so he decided to see if he could outwit the clever Quetzalcoatl by challenging him to an impossible task, asking him to play a proper song on a Conch Shell with no holes. Quetzalcoatl could not blow a Conch with no holes but he got the idea to fill it with BEES and their buzzing would create noise which Quetzalcoatl used to make music, thwarting Mictlantecutli's impossible task. Reluctantly Mictlantecutli negotiated with Quetzalcoatl to arrange a mortal lifespan so eventually he would get the bones back, but after Quetzalcoatl left with the bones he grew angry again and sent his minions to mess up Quetzalcoatl along his way to escape and caused him to break some of the bones on his way back to the surface (Which didn't really do anything bad but is the explanation for the vast diversity of human shapes and sizes.
I imagine Mictlantecuhtli is not the most malicious antagonist to Quetzalcoatl but he does hold a grudge and will try to make Quetz's life harder with more challenges that he might just find entertaining trying to outsmart the God of Knowledge, but he's also a God of the Dead so putting mortals in peril is of no consequence to him since he will just receive their souls afterward...that might even be an incentive for him to want to cause lots of death. More Death means more Bones for the Bone Hoard (And he likes eating people's eyeballs). He does not adapt with the times and refuses to do so; Even in Aztec myth he was already sort of considered a stubborn old man who is set in his ways.
Tlaltecuhtli is the Aztec God of the Earth and the Giant Human-like incarnation of the Primordial Crocodilian Chaos Monster Cipactli, who is specifically a Female monster, and then becomes a Male God. Tlaltecuhtli is canonically a Trans-Masc God though they also sometimes are considered nonbinary being called "Our Mother, Our Father" who is also one of the most powerful gods feared by all the others.
As Cipactli, she was a supermassive being who swam the primordial oceans of chaos before the gods consuming everything in her path with mouths on every joint of her body that are always hungry. Whenever the gods tried to create anything it would fall into the Primordial ocean and get immediately consumed. In order to stop her, Quetzalcoatl and Tezcatlipoca teamed up for the first and possibly the last time, since Tezcatlipoca used his leg as bait which is how it got bit off; A wound that will never heal and always hurts as though the bite was fresh. Then once on the surface they attacked Cipactli with all they had till she was defeated and bound up but not dead using her body as a foundation to create the earth. Over time of remaining dormant and ever hungry, Cipactli split off a fragment of their being and created the form that became known as Tlatecuhtli "Ruler of the Earth".
Tlatecuhtli holds a grudge against both Quetzalcoatl and Tezcatlipoca for tricking them, beating it into submission, and then binding them for all eternity. They are an actual Monstrous Giant and a literal force of nature who wears human bones, they don't really have a reason to try to blend in with society.
The Ahuiateteo are a group of Five gods who are basically the Aztec version of the Deadly Sins, although, rather than "Sins" as we understand them from a Eurocentric perspective, these 5 gods represent 5 behaviors that were not in themselves considered abhorrent, but to be done in Excess becomes dangerous. If you do any of these 5 behaviors at most 5 times in one day then that is too much.
They are
Macuilmalinalli "Five Grass" The God of Wasting Time
Macuilcuetzpalin "Five Lizard" The God of Sexual Pleasure
Macuilcozcacuauhtli "Five Vulture" The God of Gluttony
Macuiltochtli "Five Rabbit" the God of Drunkeness
and
Macuilxochitl "Five Flower" The God of Gambling and
They all serve directly under Tezcatlipoca. While some of them are Animals they can take human form and blend in with the modern era running different branches of a criminal syndicate basically providing people with the kind of pleasure they each represent.