Warlock – “Raelag’s Offer” [Campaign 4, Mission 5]

I also couldn't complete mission 5. I captured 2 towns, then encountered Grok in the center, and he defeated me. I replayed, taking "Skilled Darkness" in mission 2, and in the upper right corner of the Dragon Castle, I acquired Vampirism + Dominate, which are on the 2nd level. After that, the problems in mission 5 disappeared; I defeated everyone without losses, only losing 5 dragons after 2 Demon Castles and Grok, but I converted them into Black Dragons and stopped losing them. I mostly used only one spell: general slow + general weaken; enemies practically stop moving. If anyone still manages to injure me, Vampirism replenishes all losses, and I can Dominate the enemy so they sit still and don't die prematurely. I rarely used Chaos magic, sometimes finishing off enemies with "Freezing Cold." I was lucky; it's a pity that Light didn't appear, as it has equally useful resurrection and mass speed spells like Vampirism and mass slow in Darkness.