Nexus Clash

This can't be an intended mechanic... Can it?
Since undead pets are immune to all death damage, including death auras from other liches (aren't they? I ran a lich last breath, and I think that was the case, but don't remember fights with other liches that well), and elementalist fire pets are immune to fire auras, so... Shouldn't water pets, who are immune to impact damage, be immune to the Eternal Soldier's kick auras?

The water pets should be immune to impact damage and immune to the natural ES aura.

However, ES do have the Way of Fire skill (https://wiki.nexusclash.com/wiki/Way_of_Fire) that lets them change their Aura to do Arcane for 15 minutes at a cost of 2AP and 10MP. It's mentioned in the Way of the Whirlwind skill page: https://wiki.nexusclash.com/wiki/Way_of_the_Whirlwind

So, if you find a ES, they likely won't have it up and your water pets can have free attacks. But, if the ES is active, they can turn this on and your water pets are in trouble.

Check the messages. Were your pets taking impact damage or arcane?