Perverted mind

Kird, could you please attach a save file from before the battle where your Berserk ability doesn't trigger? I'd like to check what the problem is and see if it works for us.
By the way, my main hero, Gunnar, is an expert in fire magic, but he doesn't have Berserk yet, although I hope to teach him. I'm playing as the Dungeon faction; I've already finished the Red (Necromancer) faction on 2-1-3 and am now looking for ways to defeat the Green faction.
I liked that it became "not boring" almost immediately: the first enemy showed up on day 6! I soon switched from active defense to offense, and the Necromancers fell without much difficulty (although they did give my army a hard time).

Added after 10 hours 49 minutes
Well, I've finished it. Mostly, it was similar to hunter98's experience, but the final battle with the capture of Zangiazar happened on 2-4-5, i.e., day 54.
An interesting episode was when I was about to go through the garrison to the Green faction, their main hero, Daremith, came to meet me and slipped past without attacking. I tried to attack her myself to assess the balance of power, but it didn't work out: it happened in the area of transparent ponds behind the garrison, and the battle went badly for me due to the enemy using expert water magic. That is, even Berserk was applied, but it didn't help because she immediately removed it with Healing. As a result, I reloaded and didn't attack her, but went on. I captured the first city in the northeast, learned Prayer, restored mana, then defeated the carelessly approaching Andru, went further west, and captured Zangiazar when a weak hero was stationed there in the garrison.
Perhaps the victory conditions should be made standard, so that the player has to bring things to a conclusion: then it would be more difficult for the player.
Thank you for the map!