Warlock – “Cultist” [Campaign 4, Mission 3]

I decided to play through the campaign as the Hero, and...

Up until this mission, everything was going more or less smoothly, but now I can't capture the first castle *_* Railag is on the eighteenth level, I've explored all the upgrade locations in the previous missions, he has a strong Chaos build (with all spells up to the 4th level), basic summoning (phantoms), and spellcasting... Shadia has Darkness, Mind Control, and Phoenix. Both are defeated by the hero sitting in the first castle - that hero has more mana than I do, resistance, a lot of troops, and he doesn't leave the castle at all. Shadia dies after killing about half of the enemy army, Railag about 4/5, but it's after these 4/5 that he runs out of mana, and the enemy starts spamming resistance and dealing painful damage with spells. What should I do?:smile35:

For me, this mission is undoubtedly the most difficult in the Hero campaign, including the expansions. The main thing here is to survive the first few weeks, and then it will become much easier.
And why does Railag only have spells up to the fourth level? By this mission, Railag and Shadia should have all possible spells, except in rare cases.

I'll tell you how I played through it, as I recently replayed the Hero campaigns.
I developed Railag through Chaos, Summoning, Education, and Spellcasting, although he only managed to learn Spellcasting in this mission. Shadia was developed in the same way, but with Darkness instead of Summoning. I think Summoning is a very useful school in this campaign. Thanks to it, I passed the fifth mission by going straight through the garrisons, rather than taking detours. And in general, there are situations where the Phoenix is more effective than Chaos. In the last mission, the Wasp Swarm was very helpful, especially with Railag's special ability.
In this mission, I divided the army, giving the majority to Railag and a small part to Shadia. Railag took the castle, and again, the Phoenix was more effective here. I immediately sent Shadia down to capture the mines, because even during such a siege, you can't forget about the economy and developing the castle, preferably upgrading to Hydras as soon as possible. Then I hired secondary heroes for scouting. Railag replenished his mana and immediately went to capture the second castle. Then, according to the script, a Demon should appear, but in version 1.6, the scripts are a mess, and in this case, the Demons didn't appear at all, but just stood in place. If the Demon had appeared, it would have been even worse, and as it was, it was a constant siege by high-level Warlocks.
The same problem occurred in the fifth mission for Isabel, when Agrael and other Demons didn't come to besiege the castle, and also in the third mission for Feadan, when the Necromancers attacked sporadically, and because of this, the quest to liberate the area didn't open until I went out and attacked them myself.
Next, buy as much of the available army as possible and defend against the high-level Warlocks, preferably in the castle, and continue to gather mines as much as possible, it's good if you can quickly get to upgraded Hydras. After defeating the enemy heroes, don't forget to check the taverns, as sometimes the defeated heroes come there. If you buy a few, the mission is practically complete. You can safely send Railag in one direction and Shadia in another, and the purchased Warlocks 20+ will be able to defend the castle and capture even more mines. By the way, you can send one of the purchased low-level heroes as quickly as possible to the portal at the top, where there are a lot of gold chests, although there is a risk of encountering an enemy. When you buy enough Warlocks 20+, the computer will often run around with low-level heroes, often not Warlocks, and it will be easy to win, just capture one castle after another.
But before the third mission, it's advisable to upgrade all schools to the expert level, so that you can learn all possible spells in the second mission. Also, maximize the Irresistible skill, as there will often be Warlocks with a high resistance skill. And of course, Arcane Wave, and Elemental Sense are also useful, and Education and Magic Affinity are very necessary, as you will be very short on mana. Spellcasting is also desirable, at least to some extent, but I wasn't lucky.

That's how I played through it. The main thing is to survive for at least two weeks, until you defeat several enemies and buy at least some of the defeated Warlocks, and then everything will be easier.
If it doesn't work out, I can recommend a few good videos on YouTube about playing through the campaigns, they helped me in some missions when I started playing as the Hero.