The “Island for One” scenario.

Please tell me how to defeat the orange player. As soon as I capture the last yellow castle, powerful orange mages appear in all four corners, and then things go downhill. I almost simultaneously capture all my castles. I can only defeat one mage by staying in the upper left castle (Academy). And my army remains – 300 archers and 150 zombies. I can't gather any more troops anywhere, and I can't defeat any more mages with this army. That's for sure. Is there any secret? Maybe I started too quickly? Difficulty level: Veteran.