It's just another easy-peasy conditions. Literally you can't use magic cards at all in this battle, which means you will depend solely with melee card and ranged cards. Ranged cards have more important roles for they are more flexible to attack from the rear position. Without magic cards, armored cards become a pure addition to the health parameter, and therefor Protect become a sought after ability. So let's see the detail of this ruleset.
Peakd : https://peakd.com/hive-13323/@kid.miniatures/battle-mage-secrets--lost-magic
X :

BATTLE MAGE SECRETS : LOST MAGIC#SPLINTERLANDS#SPLINTERTALK#PLAY2EARN#LEOFINANCE#BDVOTER#NEOXIAN#ONEUP#LOST#MAGIChttps://t.co/jq2FYd7eaF

— Kid Miniatures (@kid_miniatures) June 24, 2024