On the first day, I defeat Kifrah (level 5). It's strange, if I defeat her on the second day, she becomes level 19! It seems clear: it's all about the scripts. But here's the question: Kifrah is very eager to leave the battlefield, which is not good. So, I replayed the battle to defeat her and discovered the following: Kifrah has no artifacts, but with some probability, her troops can only receive 50% damage from Raileigh's devastating magic. I don't understand what kind of skill she has. I had to use more powerful spells instead of lightning so she wouldn't run away.
Playing on Hero difficulty.