Kirito is a "solo" player, a player who has not joined a guild and usually works alone. He is also one of the few who had the privilege of playing during the Sword Art Online beta period. His in-game alias, Kirito, is created from the first and last kanji syllables of his real last name and first name, respectively: (Kirigaya Kazuto).
In the real world, he lives with his mother and younger sister in a family of 3. When Kayaba announced the start of the death game, he was surprised, but unlike everyone else, he quickly came to terms with it and accepted it to some extent.
He invited his friend Klein to come with him, but Klein had to find his friends in the game. He was invited to join them but declined as he couldn't handle the pressure of their defense, even with his knowledge of the game's beta testing.
Kirito usually uses a one-handed straight sword. The blade he uses the most is the Elucidator. He later acquires a second blade called the Dark Repulser, made by his blacksmith friend Lizbeth.
