Abracadabra! Or in your case: !אברא כדברא
I was unclear I think. The trading card game Magic the Gathering uses target as an adjective simply out of convenience; so why shouldn't we use ethos as a plural word?
Why shouldn't we use ethoi when it sounds fun? Go ahead, use it. I just don't want people to pretend it's correct because that's what it would be in greek. If you want to say it's correct because people use it, there is very little point in arguing that fact.