I pronounce it in my head as "De-Ge-Ka" because phonetics.
Aether means "pure air", and I've used an Aetherion as a class before. I could also recommend Purimancer and Aethamancer.
Modern BGM's... Darren Curtis has three tracks I would use for Modern City. "Triumphant Celebration", "Radiant Times", and "Highland Castle" could all work for large modern cities. I'll have to do some research on this one for you.
Horo? It's either a name or a slang term for a "morally ambiguous male".
When combined with Hora, I'll cut the joke, and just say that it makes me think it's a Noun used to describe a kind of people, or maybe a given name.