Let me explain how I played this map.
In the first two weeks, I cleared all my territory, except for the undead on the portal and the neutral Necropolis. By the third week, I had built Priests, Paladins, and Angels, and I also had a Castle (I didn't build Griffins because they aren't needed here). In the fourth week, I was already training 20 Swordsmen into Priests, and naturally, on that same week, I broke through the portal to the Dwarves through the undead. After gathering resources there, I went back to my base, and the following week, I headed to the second garrison. There, only the second month had just begun. And so, everything seemed to be going well; I had all the upgrades, and the game was progressing smoothly, but when I take the enemy's Castle and settle in for defense, this little guy doesn't attack me. Indeed, why would he?
He's a smart guy and goes straight for my Castle, ignoring me.
So, here's the question: how do I defeat these cunning Dwarves, because they won't attack you in your Castle, and going head-on against them is suicide. If you win once, it's with heavy losses, and you won't be able to recover.