Akihiko Kayaba

Director and creator of the Nerve Gear and Sword Art Online. He traps all the players within Sword Art Online by using the Nerve Gear to cease sending signals to the users' body. Any attempt of 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.

He is in fact Heathcliff in the game SAO, who is the leader of the guild Knights of Blood.