I had 29 Mana and could just play Common and Rare Units. Nothing special so far.
But the other Ruleset Option were way cooler:
Fire and Regret and Thorns for my and his Monsters! 👾
I played the Grand Master Rathe because of this Bonus stats:
Void Armor protects my Monsters from incoming Damage and the Amplify skill will maximize the Damage output from Magic reflect, Fire back and Thorns!!!
This 2 Monster only need 5 Mana for both of them! But in a Ruleset like this they are beasts even if they have no or just small damage Stats.
They reflect the Damage of you enemy and make them kill themself 😁💪