No, We Can't All Just Get Along

Question: In your game, what transpired to make the Trimurti, Quetzalcoatl and Tezcatlipoca the enemies of Odin?

Two separate events, actually.

Quetzalcoatl and Tezcatlipoca join the rest of their pantheon in hating most of Odin's guts. While the two pantheons were supposedly allies, working together and sealed as neighbors by the marriage of their children Geoff and Sangria, Odin was behind the scenes attempting to annex as much of Mexico as he could get away with, partly out of his usual Odin-esque desire for conquest and expansion and partly because he was hoping that entangling his Fate with that of the Aztlanti might help him get out of Ragnarok. The Mexican gods, embroiled as they were in fighting several Titans at the time, didn't notice what he was doing until serious damage had been done, and things eventually came to a cataclysmic and destructive head when they confronted each other. I won't say exactly what happened because it's going to be the subject of some of the upcoming stories about Geoff's band, but the rift between the two pantheons was massive and the vast majority of the Aztlanti now view Odin as a traitor to their alliance.

As for the Trimurti, in their case they were the aggressors. After having serious problems on the home front with a certain one of their members deciding to go batshit and try to uncreate a lot of stuff, they shanghaied Aurora's band into helping them defeat him and clean up the mess. Unfortunately, they didn't ask first, and being that they tend to have a somewhat lofty opinion of themselves, they really didn't feel like they needed to. When Aurora expressed some concern that their divine parents were likely to kick their asses for haring off on a trans-continental Indian adventure instead of doing what they'd been told to do, the Trimurti rolled up into Asgard and Odin's feasting hall while he was having dinner, dropped off the kids and declared in front of most of the Aesir that nobody was to punish them or they would have to answer to them. Then they went home, blissfully uncaring of the epic insult they had just delivered to the king of the Aesir, and the band had to deal with the unpleasant fallout.

While the shenanigans with the Trimurti are not ready to make it to fiction for a while yet, you can see some of the ramp-up of the problems between the Aesir and Aztlanti in some of the stories. In Foundations, the first evidence of problems in Mexico appears and the first accusations of Norse involvement are leveled; in Drums of War the Norse confirm what they're up to but have not yet erupted into actual conflict; in Bone, Muscle, Heart and Sinew Sangria and her fellow Aztlanti Scions begin dealing with the problem and attempting to safeguard their people, and in What Dreams May Come Woody's band sees the Aesir contingent hard at work in Mexico and is warned about the fighting that has begun to break out.