RTF is a global modification that replaces all towns in the game.

Well, that's not quite it; I suggest a desert-themed lizard.
With coloring similar to this one.


Added 3 minutes later
In general, all eight of our factions always adhere to one tone within a single tier, which is different from the other two tiers of that city. For example, Humans have three shades: blue for the base, white/gray + gold for the tier, and red for the alt-tier.

I had three options for the upgrade:
1) the one that exists
2) a blue lizard with bony scales and dragon-like horns
3) armor made of leather (then both it and the archer will receive similar upgrade recognition elements)

The idea of a desert lizard is only bad because lizards live in swamps and jungles, but if you search on Google, you can find a quadrillion interesting color schemes for swamp lizards.


Added 1 minute later
A gorgeous color scheme for the warrior