Kirito

Kirito was one of the thousand Beta Testers for the closed beta of Sword Art Online. After logging into the official version of the game, he and the 10,000 other players were trapped in Sword Art Online. As time went on, Kirito became known as the Black Swordsman. He later joined the Knights of the Blood due to losing a wager with its leader, Heathcliff. Kirito found love with another player named Asuna, thus marrying her in-game later on. After discovering Heathcliff was in fact Akihito Kayaba, he defeated him which eventually put an end to the game by defeating the final boss, thus clearing the game.

Other Sword Art Online survivors as well as Asuna were not logged out from Sword Art Online in the aftermath of the incident. Kazuto began playing ALfheim Online after seeing an in-game screenshot of what possible could be Asuna. After freeing the three hundred remaining captives and reuniting with Asuna, Kazuto continued playing ALfheim Online with his old friends from Sword Art Online as well as some new friends from ALO

Kazuto transfered his ALfheim Online avatar to Gun Gale Online using The Seed to investigate a series of strange murders, committed by a player named Death Gun. Kirito took part in the largest tournament in the game, the Bullet of Bullets, to attract the attention of the mysterious player. With the help of Sinon, the two defeated Death Gun in the process.

Kazuto later returned with his avatar to ALfheim Online, and continued playing it with his friends. Several months later, Kazuto was offered a part-time job to test the new FullDive machine known as the Soul Translator, but in reality was helping a secret military project called Project Alicization.