Hero leveling during the first 2 weeks.

, and sometimes on the 3rd day, you already need to go to an adjacent area and might not return for 3 weeks.

Could you elaborate on this? How can you level up for 3 weeks with 5-6 mages, even with 100 gremlins, 40 gargoyles, and level 1 units? I assume you're not just defeating, say, a horde of warmongers, but also larger and more powerful enemies? Do you need to send reinforcements? Can you give a specific example?

Added after 8 minutes
Well, if you have a ballista and fire archers, that's clear, but mages don't attack as often, and you can only quickly level up machines with Hafiz.