Wind Style: Rasen Shuriken!

Naruto arrives to finish Kakuzu, and the Wind Style Rasenshuriken is born. The episode is the payoff of the wind-nature training: a Rasengan threaded with thousands of microscopic wind blades, so dense Kakuzu's elemental masks read it as suicide to approach. Naruto lands it, and four of the immortal's five hearts die in a storm of cellular destruction. The arc's tactical mountain falls to a new technique — but the cost is already written in the strain on Naruto's arm. Kakashi's protégé surpasses his own jutsu.