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Here's a recap of the scenario I just completed:)
I played on version 1.6, on Veteran difficulty.
I didn't encounter any problems anywhere; I immediately captured the second Necropolis and continued exploring the territory. I saw a green player who was clearly trying to capture my newly acquired city, and I killed him without any problems, then moved on.
I captured the green player's city, and that ended his game. Then I went after the orange player, and killed him without any problems, not even bothering to buy reinforcements in the castle. Meanwhile, Kaspar was guarding the Necropolises. After that, I bought reinforcements and went after the blue player, and killed him without any problems. I explored the territory, visited all the upgrade locations, and completed the quests.
In the end, when I saw 993 black dragons, I was a little scared (and who wouldn't be??), but it turned out to be quite easy with my army.
Here are the screenshots: