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

Why remove the enchantment? I removed Stone Skin with Dodge and, voilà. The second point is clear: the League's archers are weak (when playing as them, I generally don't even take archers; alternative units with invisibility look better). The first point simply won't be needed when playing as Winged: the enemy will fall before they can launch any decent counterattack.