[LDiCesare]

I made a small experiment and had a cyclops+aesir nation vs. a tartarian nation. Cyclops come out faster, which may allow to get artefacts earlier on the way but their price is such that they don't get spammed as tartarians are. Of course, GoR has a price, and takes some time, but naked (non blind) tartarians can be pretty strong. When I got 1 fully kitted cycops killed before being able to buff himself by 3 tartarian monsters who flew upon him from afar, I realised my initial assessment was certainly wrong.
So I'd say the 35 gems cost looks quite balanced, although it may in fact be a bit expensive considering earth gems can be used to forge all kinds of good stuff.
The aesir is probably more affordable given air gems aren't all that useful imo, and she comes with a nice armor.