Wizard – “Haven” [Campaign 6, Mission 4]

I keep starting over and over again. I just can't seem to beat it.
If I develop slowly, Isabel has such a large army that I can't possibly defeat her. If I rush quickly without stopping, her army is smaller, but mine isn't much bigger either.
I have no idea what to do with Isabel! Her Archmages and Paladins... they're terrible!

Why can't you defeat her? I spent a very long time exploring the map – first, I quickly captured all the castles except the one where Isabel was hiding, and cleared the territory of enemies. Then I found Raileigh and Shadia – I merged all of Raileigh's troops and went to attack Isabel, thinking I had enough experience to defeat her. No way! She tore me apart like a wet rag! Well, I thought, never mind – I loaded the save, and with Raileigh, I cleared the entire map, visited all the upgrade locations (and there are quite a few of them)... The other factions captured all the mines. I built up all the castles (except for Haven, in the Necropolis, I limited myself to a Magistrate, because I wouldn't have enough money). As a result, I have a troop increase from 3 (or 4) castles, while she has only 1. After some time, the sheer physical strength has a clear advantage. You can also use the other heroes to run around and visit the upgrade locations, but honestly, I didn't feel like it... And then Raileigh went to fight Isabel... and won. The main thing is to eliminate the Paladins first (and Angels can resurrect about 60 of them at a time :)), and then the Angels. And then Raileigh rains down on the Archers and Imps. (The computer had them all gathered in one corner :D)