I love this...but Andean cultures going to Europe? Thats impossible! (But they can always invade....India! Ha! Madness!)
Yeah, the Andeans probably won't be invading Europe. They'll interact in other ways though and obviously individuals would still be able to make it.
Haha, I meant for the Aztec empire

But... no objections

Say, if you could think of one animal/symbol to symbolise the Aztec empire, like the dragon for China, which would you pick? I want to try making a button for them.
Not sure about one, but I think the Eagle and the Jaguar are probably the best animals. In terms of symbols, I've been using the Aztec pyramid (that vanilla uses as the icon for the religion) for a few things. I think the glyph for Tenochtitlan (
https://commons.wikimedia.org/wiki/File:Tenochtitlan_Glyph_ZP.svg) would look good in place of the large yin-yang in the offmap interface.
Having said that, by button do you mean the button next to the map to open the offmap window, I have made* a different one (it's in the screenshots). I used the Sun, as that's what paradox use fo the DLC, however I don't think this would be something the Aztecs would use. (Having said that I've just realised that that is the icon or the Aztec title - was it used by the Aztecs or did the devs just make that up?)/.
*By made I mean I recoloured it and plopped the DLC icon on there.
Also, as a more general point about art, I quite like the idea of having things in the style of Aztec glyphs for icons for the Aztecs. Also, I'd really like to make the Aztec news events look like stone tablets as opposed to paper. Further, I'll definitely be able to make the Aztecs use the Pagan UI in the next update, however from the way the dev's comments read it seems like UIs will be addable. If so, I'd like for the Aztecs to have a stone-themed UI (like how the Pagans' is wood-based) but that'll depend on whether it's possible and if I can do it and get the time to do it.
And my cannon is that the Aztec empire is a bit like Ancient Egypt/Modern China in regards to writing. They use the Aztec system for most things and formal things, however they've adopted the Latin alphabet or some adaptation of it (Similar to Egypt's use of hieratic or China's use of Pinyin) for education/recording sounds and stuff, so they will still be using their traditional glyphs.