I think Rikuo Nura from nurarihyon no mago
I mean a really
Rikuo: my fear make it that im an illusion that cant be touch(not attacked touched as well) but I can attack you as much as I want
Enemy: dang, but im not like every other enemy which you kill in one hit, im a boss which you kill in 10 hits
Rikuo: you know even though I have a sacred sword that attacks only yokai so you can take a human hotsage if you want I can go through both of you and the human would be safe, oh and if it doesnt kill you it dispels your power and its a wound that will never heal, im gonna fuse with a subordinate and get even stronger while you still cant attack, oh did I forget to mention my army of about 100 yokai that will attack you as well and can not consider my well being because I cant be touched so they dont need to hold back because im next to you.
Really thats to powerful.