What Does Harsh Rule Do?
Harsh Rule is currently the only 'board wipe' card in Eternal (although Stray Into Shadow comes close. When you play it, it simply kills every unit on the board. Yours as well as your opponents.
Well, almost. Enemy units that have an Aegis will be protected from the card's effects and lose their Aegis rather than dying. Remember that Aegis does not protect your units from your own spells, so your units will die even if they have Aegis. As far as I know there's no way to protect your own units from the effect of your own Harsh Rule.
This page written for Eternal version 1.17, Card Set 1
Last updated: 4-03-2017