How to deal with Lethos’s plague (Dark Elf)?

Thanks for the quick response! My hero is Wing, so hit-and-run tactics probably won't work. I'm afraid that by level 30, at the beginning of the battle, he'll cast Lethargy on everyone, and then he'll start throwing Berserk and Dominate spells while I'm trying to remove the Plague. Against Plague, I'll make Unicorns with an aura. I found the armor of the Forgotten Hero; it's tempting to take the Magic Resistance bonus, but then my Attack skill will suffer. I don't know what to do. I also want to find a cloak with Earth Damage resistance so that Plague does less damage to me. Otherwise, I don't know what else to come up with. Any advice?