This one is pretty easy if for no other reason; then that Karin has the ability to heal you during mob sections. The mob sections are not hard; you can just abuse the rear attacks when prompted and burst attacks ++. A few annoying bits when the mob enemies are the big guys, but they are easily dispatched in a few hits. No matter if you choose hero route or legend route you will have to fight groups of enemies in mob fights. Hero route just less. Just make sure to have Karin heal you between fights.
The actual fights are with Gaara (with support) and after all the mob fights you will fight Mizukage Mei (with support as well). Both fights are standard 1 vs 1's with supports. Use substitutions wisely and use ninjutsu and ultimate jutsu ++. Neither of them are are hard to beat. Play defensive when low on substitutions and donlt get caught in attacks because you don't have them The Danzo fight is not a part of this S rank making it almost too easy.