I have been wondering if Nefarox, Overlord of Grixis can get rid of Hexproof creatures with his ability ' Whenever Nefarox, Overlord of Grixis attacks alone, defending player sacrifices a creature. ' Normally, Hexproof would get around that, but since the ability targets a player, if the only creature on my opponents field has Hexproof, does he/she still sacrifice it?
Yes you are not targeting the creature even if it's the only one there.
It doesn't target the player, either, so even if they have shroud/hexproof, Nefarox still works.