I'm working on this kid's server and one of the things I'm trying to do is make special mobs spawn around the world and these mobs will have names, but I want the ability to kill them all if need be. A problem is when I try to do /killall or /butcher, the mobs with names will not die. Because of the plugins on his server, I can't do /kill @e[type=!Player], all it does is say can't find player even though that is meant to kill every entity but the player.

Any information about how to solve this problem would be greatly appreciated!