Heart of the Night

Lately, I've been feeling nostalgic for the Heroes games and decided to play something. I chose this map. I started with a hero, and things were going well. With the mage, I got carried away with combat leveling and forgot to leave space for magic skills.)
The neutral creatures are quite easy to defeat; I don't know how the lack of magic schools will affect me later. For now, I barely have any spells.

But Greta... she's just awful. In about a week or two, I cleared 2 dwellings and 1 mine with her, barely managing to rebuild the town. And then, against this level 14 Greta, who could only muster 80 archers, Ainuriel (or whatever his name is), a powerful ranged attacker at level 25, appeared. His ballista immediately wiped out all the archers, even though my army was four times larger. I don't know what I did wrong that gave the enemy such an overwhelming advantage; there was nowhere else to go, so I had to use cheats in battle :confused:

At first glance, the map looks very beautiful and interesting. Let's see how it goes from here.