I was playing 1v1 against a conqueror, and he would hit an attack then go into an unblockable bash attack. it would stun you and give him another hit. even if the first attack didn't hit, he could still use it. it blocked any attack that i tried to use to counter it.
It's done by Guard Breaking after any confirmed hit or by dodge and then GB, though usually after hit GB into Heavy combo to follow up.
To counter it, sidestep. It has no tracking and is linear, and spamming dodge will give you just enough time to get out.
If he is smart, he will switch up whether he uses it or a zoning attack.