It was as if a Demon had manifested itself and this ... Simply put, King of Hell is Zoro's strongest form. In this form, Zoro takes his swords and channels both Conqueror's and Armament Haki ...

Zoro's Nine-Swords Style ... the opponent's brain into seeing this ungodly form. "What just happened? For a moment there, he looked like a Demon God with Three Heads and Six arms." ...