I have been playing the No More Heroes game and I have reached thr rank 8 fight. I am stuck on an opponent called Shinobu. She is really kicking my butt and I can't seem to wear her down. So, who is the hardest assassin in the game?

Holly Summers. You'll see her after a few more fights. She's always the speed bump in my playthroughs. She set-up traps all over a beach, and is generally deadly from afar and close-up. It's moreso patience that you'll need while fighting her. Sometimes you just want to run straight at her and try to smack her around a bit. Bad choice.