TheComm9600

After a few matches on medium\balanced difficulty, I noticed that once I take control of the enemy city center, the enemy doesn't send troops to try to take it back anymore, 0. It doesn't even try to build proper defence apart from a few towers, almost 0 troops. I switched to difficult\balanced and it was the same, the difference is that the initial attacks were a bit stronger, bu that's it. I wish to play a difficult match, not madly difficult but challenging, how should I set the AI?

I haven't done a full match yet, I am playing right now but I noticed the AI doesn't build farms, isn'it quite unbalanced? Does it get food in other ways?