is the Director and Creator of the Nerve Gear and Sword Art Online, and is the main antagonist of the series. He traps all the players within Sword Art Online by using the Nerve Gear to cease sending signals to the users' body. Any attempt at removal, loss of power for a certain period, or if the user dies in the game will also kill the user. His motivation is to observe what happens after he traps them. Later, it is discovered that he had been masquerading as Heathcliff, the leader of the Knights of Blood. Although he can give his character immortality, he can easily defeat other players without it because he already knows how to counter the skills that he designed. Defeated by Kirito at the end of Volume 1, he died, leaving behind a program that granted Kirito the World Seed, at the end of Volume 4. His death was his own doing since he had also rigged his own Nerve Gear device to fry his brain when he was defeated.
Tōru Ōkawa(Heathcliff), Kōichi Yamadera(Kayaba)