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I agree that secondary quests should be tied to the main storyline, i.e., either strengthen the hero upon successful completion, thereby preparing them for encounters with the AI (but if the AI is weak, this is not necessary), or be a necessary link for continuing the plot on the map, or provide an alternative path to the final battle. "Ancient Evil" is easily defeated. In battle, only Death Knights, recruited at the portal with double strike, retaliation, and the main ability – deadly strike (which reduces the enemy army by half in 25% of cases), are used. The Death Knights are placed one by one in cells, resulting in 5 squads of Death Knights. "Reinforcement" with a devastating strike is cast on one of them, which delays the turn of the squad of 100 Ancient Evil knights on the initiative scale and also instantly deals 50,000 or more damage (I don't remember exactly). Among the artifacts on the hero, there should be a staff (reducing initiative by 20%) and any other artifact from the necromantic set; together, they reduce the speed of enemy creatures by 1, which is extremely important. As a result, the Death Knights of Ancient Evil have a speed of 1, and a high initiative of -16. Ancient Evil should not be allowed to gather an army – even 20 skeletons with 5000 attack and defense will cause problems. And one squad of Ancient Evil's Death Knights is easily reduced by half by our knights. It is important to have the "Fight to the Last" defense skill. This allows them to withstand the first strike of Ancient Evil's Death Knights.