No, I gathered an army there, periodically clearing out the blue creatures that emerged near these cities, and when they (seemingly) no longer had particularly powerful heroes left (I bought a couple of level 18-19 heroes), I left Shadi in the first castle and went north with Agrael. And for some reason, the blue creatures surrendered all their cities one after another. And here's an interesting point: it turns out that you don't have to eliminate the demons, and if Railag takes the last 7th castle, it still counts as completing the mission, except perhaps that you get fewer points for this campaign in the Top 10 games:smile13:. And therefore, before taking the 7th castle, it is advisable to finally get Shadiya out of the capital and go north to clear out these 3 groups of demons led by Grol, and then take that castle. Another trick is that they both gain an extra level if they haven't reached the maximum for some reason. So, they ended up with 26 and 25 levels, respectively.
P.S. I'm playing on Recruit mode because the game should bring pleasure, not nerves:rolleyes: version 1.60

I play on the hero difficulty because I feel dissatisfied when playing on easier levels.
If you don't sit and accumulate, then in the first week (if Railag has logistics), you can easily take three castles and buy out the growth. That's what I did when I played through it. I took one southern and two western castles. And then the issue is practically resolved. At the beginning of the second week, a killed strong hero, or even two, is bought back. They have a huge advantage over Railag and Shadiya, and not only because they are level 22, and our heroes are level 18. They can scatter at any moment. Therefore, it is convenient to send them ahead of Railag with single assassins. When an enemy is detected, the bought heroes attack first, destroy most of the army with magic, and scatter. Railag finishes them off. The scattered hero is immediately bought back in a convenient castle. Also, a leveled-up hero can take a castle alone, if he has single hydras. Additionally, he can, by scattering, "teleport" to any castle near a neutral, when approaching the castle of a strong enemy. The main thing is not to have too many troops on hand, but to keep them in the castles and not clear out all the neutrals - you can do that later.
By the way, there was a funny situation with Kifira, whom I managed to get on the first turn. She was level 5, but when she appeared in the tavern at the beginning of the next week, a script was triggered that gave her level 22, and windows with skill choices popped up, and I didn't hesitate to give her the most important skills.