Kyouji is a player of the American produced VRMMORPG Gun Gale Online. He uses the AGI powered character Spiegel. He is Asada Shino's friend and the one introduced her to GGO. He is a son of the director of a hospital. He later develops a hatred towards Zekushido, as well as other STR-oriented players, for destroying Spiegel's development by suggesting AGI as the way to power provoking him to boost AGI, but being unable to wield heavy guns due to his lack in STR. He also later develops a stalker attachment towards Shino, resulting in him attempting a homicide and suicide together with her, only to be foiled by Kirito, almost being killed in the process. He also played the role of Death Gun when Zenkushido and Usujiro Takaro were killed. In the end, he and his brother were arrested by the police. (Source: SAO Wiki)
A member of the guild Knights of the Blood assigned to protect Asuna. He was later revealed to be a member of the famous Player Killer guild, Laughing Coffin. He later tried to kill Kirito by setting a trap and killing three of the guild members. He was later stopped by Asuna and killed by Kirito because Asuna couldn't bring herself to kill him.
He is the leader of the guild Black Cats of the Full Moon he and the other members (not including Kirito) are actually computer research club members from the same high school in the real world. One day, Keita went to buy a little house as their guild home and after he got back Kirito told him all the other members died after they got attacked by monsters. Keita then ran out of the town in Aincrad, and jumped over a fence without hesitation committing suicide by jumping in the endless void.
Akihiko Kayaba is the 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 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. He is in fact Heathcliff in the game SAO, who is the leader of the guild Knights of Blood. This was found out and revealed by Kirito after the defeating of the boss on the 75th floor. Because of this, he offered Kirito a chance to beat him in the duel with the condition that if Heathcliff is defeated, the remaining players will be able to log out. After a fight in which it appears both Kirito and Asuna are defeated and killed, Kirito, with his final efforts, managed to use Asuna's rapier and stab Heathcliff through the chest thus defeating him and clearing the game. It was later revealed that neither Kirito nor Asuna died and in the final moments of the game Heathcliff personally congratulated Kirito on winning the game, saying that he was the one he had an eye on from the beginning due to his amazing reflexes and reaction time which granted him the use of <Dual blades>. He then faded away along with the virtual world he created. In the closing moments of the ALO incident when it appeared Sugou had defeated Kirito and Asuna due to his GM status, Kayaba reveals himself with a even higher status as the game's creator (ALO was made from a copy of the SAO server) and allows Kirito the chance to have a fair fight with Sugou in which he easily wins thus recusing Asuna. Kayaba then gave Kirito a "seed" which he said that he leaves its fate to his hands. Whether to delete or forget it is fine, but if he did have some lingering emotions for Aincrad then he would ask Kirito to let it bloom. It was revealed in the aftermath of the ALO incident that Kayaba is indeed dead, his body found five months after the game was cleared. Before his death however he scanned his brain with the success rate being very very low, but he was apparently successful but it burned his brain resulting in his death. This copy of himself was the one that helped Kirito when he was fighting Sugou.
A merchant stationed at city Algate, located at the 50th floor of Aincrad. His shop motto is "Buy cheap and sell cheap." He is 180cm tall, has dark complexion and has a rare hairstyle which is bald. He is also a very strong axe-wielding warrior in the frontlines. Kirito sometimes stays in his shop as sort of a disaster shelter, which he gets annoyed with but later ignores as Asuna also visits, which results in some publicity for his shop. In the real world he is married and owns a Bar called Dicey Cafe. In the side story Aria in the Starless Night, he is among the few players who participated in the first floor boss fight and supported Kirito when he knew of the latter's status as a beta tester and later called a Beater. Upon returning to the real world he helps Kirito implement Kayaba's "seed" which allows VR games to be easier accessed throughout the world, also vastly decreasing the large licensing cost that companies would pay in servers.
Kovats is a lieutenant-colonel in the Aincrad Liberation Force in Sword Art Online. He has a gung ho attitude. He drives his men to their limits, giving them no rest. He was killed by The Gleam Eyes after his party entered the boss room without any major preparations. (Source: Sword Art Online Wiki)