Defensive gameplay and other tactics.

He will mercilessly destroy his own warriors! In my opinion, it is very clearly stated that it affects his own warriors. Sending your unit to the enemy means completely destroying it; it's okay if it's not a very useful unit, although I don't know of any such units. But if it's archers, as a rule, such spells are cast on the most dangerous units. Why not just use a dispel magic spell?