Walkthrough for the "Tribes of the East" expansion.

Make sure you have plenty of gems and ore by the time Wolfstan attacks the Castle.
However, there can be no auto-battle there. This is a battle that you need to conduct yourself.
Then you fight and periodically resurrect your units with this rune.
When your creatures' turn comes, there will be a row at the top with a selection of runes. Look for the resurrection rune. Applying it makes the battle easy.

I'll explain again :) In the 3rd mission, playing as Zehir, Zehir needs to give away the extra items (and not just those, for example, the Sar-Iss ring) to Wolfstan. We level up Wolfstan by a couple more levels. And, as Pearl said, have more ore/gems for resurrection runes (remember the triple price for repeats).
+ As far as I can tell, resurrect doesn't help much there, it's much more effective to use Divine Vengeance

Added 18 minutes ago

I can't capture the third Inferno Castle with Orcs in the last mission. The Demons have a much stronger army. And I'm given a Shaman instead of a Hero... They defeat me quite easily... Help!!!!

The Orcs have some kind of special battle cry. I don't remember what it does :D, but it helped a lot.

Here! I found it about the battle cry----------------

Anger of the Horde
Level: third (3)
School: Warcry
Mana required: 10
Hero level required: 11


The selected enemy unit takes damage equal to the number of creatures in the hero's entire army.
Also, increases the fury of all creatures of the Barbarian Castle by 40 points.
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And in general, I wrote at the very beginning of the topic that Wolfstan, Frida (I remembered :D), Kuzhin, Ilaya, and Bear herself - Zehir will be besieging the red castles.
Zehir needs to save the Titans, + along the way, you need to collect magical troops - Magicians, Air Elementals, Gremlins, Rakshasa, etc. from all over the map, where they are, they join. + I actively used the Phantom and Banishment spells