PSA: Riposte spell works with Medusa's ranged counterattack.
Riposte mastery skill also works.
Yeah, just let them shoot your Medusa, and you can pretty much clear the ranged squad like a Minotaur clearing the melee squad.
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For newbies who don't know what I'm talking about:
Riposte spells give you a "parry" ability, so you can counterattack before the opponent's about to attack you.
So if a ranged unit tries to shoot your Medusa, the Medusa will shoot it first;
If it kills the stack, your Riposte mastery skill will reset your counter attack, so you will see all the ranged squad tries to attack your medusa, and gets eliminated in one turn.