Doe anyone know where their source of horses is? We could pillage it together with their iron resource and gain a moral victory at least. I mean, being able to defend only by building archers can be quite demoralizing.
Regarding that stack, I think that it's a counterattack against our city Victory. If they advance next turn, we could withdraw our axeman back to the spice jungle and fortify.
We're currently the rulers of the seas, so let's make use of that advantage. We can ferry troops faster than they do so let's overwhelm them by attacking at multiple directions. Galleys will play an important role in this.
Also, if CBR continues to attack, Yellow Destiny will lose eventually.