Son of the Devil

If it weren't for the markets, this wouldn't be happening. And with the Rogues, isn't this a mistake? The other Tier 1 heroes guard reasonable armies.

Added 11 minutes later
In my opinion, the conditions for Ilia are too difficult. She is the weakest of them, and the army guarding the sulfur mine can be defeated, but with noticeable losses, and where are the reinforcements? She had tougher challenges before. But with Railegh, everything is balanced – a strong mage with a ring can pass with a minimum army.
Also, I don't know what the final goal should be. Is the priority the specificity of the upgrade or the amount of troops?

Added 14 minutes later
Maybe give Ilia the Ice Bolt spell so that she can at least compensate with elemental damage.

Added 36 minutes later
It would be good to swap the positions of Ilia's and Railegh's castles in the list, or the heroes themselves, if each is in charge of their own castle; it would be easier to navigate and see what to build. Perhaps the game allows this, but I just don't know how to do it.