Light magic has not been canceled yet. Removing the plague curse is a great way to heal. And the tactics will be more similar to the tactics against a demon, as the main force will be dark magic. So, we definitely need light (preferably with antimagic, curse removal, and teleport). Also, you need to consider the greater danger of hit-and-run compared to a demon. A lot of heroes with agile units can eliminate many units, so be careful. Countermeasures: 1) a rain of arrows with keen mind and cursed agile units (if you're lucky, you can take down a hit-and-run unit in one shot without losses) 2) you can also invest in dark magic yourself and take the cursed lands perk or the unholy word spell (and vampirism will help in battle). Then plague, mind control, and berserk will not be a problem) 3) if the hero is Wingael, leveled up in speed, then all your units will reach his agile units before they move.