Hmm, this is a rather strange behavior of the script. I don't remember seeing such a battle from anyone else. I need to check everything again.
Good luck in the next missions.
So, Krigan summons undead, and it's impossible to win with such an army. He was left with 0 units, but the hero didn't die. I thought I'd finish him off to see what would happen. Thanks to the Mana Eater, I had enough mana, everything was fine, and we finished him. But in the end, it says that your hero has no creatures, so you're in the tavern, and the next cutscene shows that you lost.
Please fix Krigan; the campaign is interesting, but the boss is too strong.