I just found the Diviner troop for the first time. I immediately went to level it up, then checked traits. The traits showed an exclamation point, which if I’m not mistaken means something in that menu can be upgraded. However, I wasn’t able to afford the exorbitant cost for even the first trait. The costs for the second and third traits look reasonable. For the first trait, however, this is what was listed.
106 minor nature
22 major nature
6 major earth
12 runic nature
12 runic earth
6 arcane forest
I don’t believe even mythic troops require arcanes for the first trait. And this is ultra rare.