I know this post is old, but. I would kill with Invisibility potions. Since I play ghostcraft. Where you are a ghost in no armor that has only a wood sword and a few tactical items. (my favorite are the shears. They let you insta kill non moving targets. All the others are bombs.) but you fight many soldiers that have sharpness one iron swords. If an invisible man can kill a group of eight people using a wood sword, I think it might be a bit op.
-EDIT: I forgot, the ghost can sap hp for every hit. and thats what keeps it alive.