The very poor roads led to the late game. I had just gained full control and was preparing to double my 10 Archons, but Kirr attacked the main castle, which had +20 defense against my units (and -20 to magic).
In the final, the key moment was the unexpected resurrection of the Archons, even though they had Efreet on their side: another hint for both of us. After gaining the first initiative, I removed the anti-magic from the ducks; otherwise, I would have had to use earth elementals.
Thank you for the game!