Kirito

NOTE: All battles involving Kirito, will involve his game avatar's weapons and appearance, however, they may operate on "game logic" or "real logic" depending on the opponent."

Kazuto Kirigaya was a normal teenager in 2020s Japan, who was selected to as a beta tester for the virtual reality MMORPG Sword Art Online, for the new Nerve Gear console. After a month of beta testing under the screenname "Kirito", a portmanteau of Kiri''gaya Kazuto, his name by Japanese conventions (family name, then given name), Kirito logs on to Sword Art Online for the official release. Kirito quickly makes friends with a new user under the screen name "Klien", who discovers that the log off button is not in the menu like it was in the beta. Kirito, Klein, and all of the other SAO users are then teleported to the starting city, where they are met by a mysterious entity claiming to be game creator Kayaba Akihiko, who tells them they he has trapped them in the world of Sword Art Online by incorporating a microwave emitter in the Nerve Gear. Any attempt to remove or destroy the Nerve Gear from the user will result in the activation of a microwave pulse that will literally fry the user's brain, killing them. If the user's avatar is killed in the game, they will also die in real life. Akihiko states that he will not release the users until the game is completed- all floors of a 100-story monster-filled dungeon are cleared. To prove his power, Akihiko changes all users into their real-life appearance- achieved by using biometric data gathered during calibration of the Nerve Gear console.

Over 2000 died in the first month, and the first floor was yet to be cleared. During his fight to clear the first floor, Kirito teams up with a girl named Asuna Yuuki. Together, they defeat the boss of the first floor, then go their separate ways, however, Kirito would meet Asuna again later, eventually becoming in-game "husband and wife", and boyfriend and girlfriend in real life after they escape Sword Art Online.

After meeting Asuna, Kirito goes on to join a guild known as the Black Cats of the Moon, and become friendly with a girl named "Sachi", though never sharing her feeling for him. Sachi is traumatized by the sheer gravity of her situation- literally being in a game of life and death, even contemplating suicide by jumping off a cliff in game and activating the microwave device upon the death of her avatar, however, Sachi is too cowardly to do even that. After several months, the Black Cats of the Moon gain enough money to by an in-game house. While the guild leader goes to buy a the house, Kirito, Sachi, and the others go to the "front lines"- the unexplored parts of the dungeon, and are killed when they fall into a trap baited with a treasure chest and all except Kirito are killed by a horde of monsters. Kirito is affected by Sachi's death in particular, and becomes depressed for several months, on Christmas Eve, he fights an event boss, Nicholas the Renegade, who was said to possess and item that will revive a dead player. Kirito defeats Nicholas, almost dying himself, but discovers the item can only revive a player ten seconds after their avatar's death- by preventing the activation of the microwave. Kirito returns to his room at the inn in despair, where he remembers a gift Sachi game him and told him to open on Christmas. In this package is a voice message, where Sachi tells him to remain strong even if she dies and to escape and live again on the outside.

His resolve strengthened, Kirito fights his way to the 75th floor, joining an elite guild along with Asuna, the Blood Knights. On the 75th floor, he discovers that the leader of guild, "Heathcliff",  is actually Kayaba Akihiko himself. Kirito challenges Akihiko to a duel, discovering that Akihiko has turned his avatar into a non-destructable object, effectively making him invincible. Akihiko reduces Kirito's HP to zero, however, he does not die due to a glitch in the game, and Kirito is able use the same glitch to to kill Kayaba. After Akihiko's death, Kirito and all other Sword Art Online players are released from the game. 

Kirito goes on to play other VRMMORPGs and to privately investigate other cyber-crimes occurring within such games.