Up to you. You can do it either way. You should probably just specify.
I was actually thinking something along the lines of "brutal someone who voted him" but that's more of an evil power, so maybe not. We'll have to talk balance sometime this week. I've got a whole list of roles with flavor that we can pick between.
If you have a targeted brutal restriction, then usually it's "brutal wolf that NK's you / brutal any player that voted for you". We just don't see those kinds of restrictions often. Shrug. Nothing wrong with them, of course. Use what you like. We can figure it out.