I was testing out the Bone Dagger special with a friend in the duel arena. He's 78 defense, and no matter what I hit, I got his defense down to 27. With another friend, I tested it in the wilderness. I only did one trial, but I hit a 12, and his defense only decreased 3 points. Also, earlier in the duel arena, someone hit a 28 with the bone dagger special on me, and my defense wasn't lowered at all. Does the special only have an effect on people lower combat than yourself?