Ranger - "Higher Vampire" [5th Campaign, 5th Mission]

People, can I ask a question? Where can I find the Shackles to prevent Nicholas from escaping? I didn't find them near the Prophet (where the spectral dragons are). And where are all the dragons? I've already killed about 3 groups, but there's still no sign of them. Kolya keeps being resurrected. I've already beaten him three times; I have a large army, and everything seems to be going well. But he keeps escaping. And then, a larger army attacked him (he had roughly the same number of troops), and he defeated me easily... I don't understand anything at all... A friend advised me (he's a good strategist and easily completed this mission): to capture all the Necromancer Castles, then Nicholas's troops will weaken, and I can finish him off. But I'm reading all your comments here, and I don't know what to do. I can't bring myself to start the mission over again. I'm going to try to capture all the cities and find the dragons now. I don't know if it will work. Anyway, that's my situation. I've probably replayed this mission about 5 times, but it's pointless. And my character is well-developed... Chaos and Light magic... damn it.

Added after 5 hours and 39 minutes
Okay, that's it. Send me your save file. The game version is 1.3. I'm begging you. I can't complete it. He's locked himself in a Castle. I have a great army, but when I attack the Castle (the last, only one), I get completely destroyed. Even the tavern says I'm stronger! Aaaaaaaaaaaaaaaaaaaaaaaaa!