In the year 2022, the Virtual reality Massive Multiplayer Online Role-Playing Game (VRMMORPG) Sword Art Online (SAO) is released. With the Nerve Gear, a VR Helmet that stimulates the user's five senses via their brain, players can experience and control their in-game characters with their minds. But an unexpected event occurs on November 6, 2022 when Akihiko Kayaba, the creator of SAO, prevents the players from logging out. Akihiko issues them a challenge; if they wish to be free and log out of the game, they must reach the 100th floor of the game's tower and defeat the final boss. However, if their avatars die in the game, so will their bodies in the real world. As the game's 10,000 players try to accept their new deadly predicament, Kirito, a skilled player who tested the beta version of the game, is determined to reach the 100th floor and be free.
Kirito (キリト) Voiced by: Yoshitsugu Matsuoka
Real name: Kirigaya Kazuto (桐ヶ谷 和人)
Kirito is a solo player as well as a beater (stands for beta tester and cheater), a player who hasn't joined a guild and usually works alone. Kirito is also one of the clearers in SAO. When it is announced that the players of Sword Art Online can no longer logout, he is surprised like everyone else, but he quickly gets over it and accepts it, to an extent. He mainly uses a one-handed sword "Elucidator" and usually wears all black in-game, as it adds to stealth, and gives him his nickname "The Black Swordsman" (黒の剣士 Kuro no Kenshi). He can also use two blades at once, a unique skill to him and he only uses it in emergencies to avoid attention for being one out of the two people to have unique skills.
Asuna (アスナ) Voiced by: Haruka Tomatsu
Real name: Yuuki Asuna (結城 明日奈)
She is a friend of Kirito and is a sub-leader of the guild Knights of Blood (KoB), a medium-sized guild of about thirty players, also called the strongest guild in Aincrad. Being one of the few girls that play SAO, and even more so that she's extremely pretty, she receives many invitations and proposals. She is a skilled player earning the Title "Flash" (閃光 Senkō) for her extraordinary sword skill.
Klein (クライン) Voiced by: Hiroaki Hirata
Real name: Ryōtarō Tsuboi (壷井 遼太郎)
A friendly player that meets Kirito at the start of the game and quickly befriends and learns from him. He and Kirito later separate because he has friends who were also new to the game, and since he was taught by Kirito who was an experienced player, he couldn't leave them. He uses a katana to fight and leads a party.
Silica (シリカ) Voiced by: Rina Hidaka
Real name: Ayano Keiko (綾野 珪子)
One of the rare beast tamers in the game. She usually stay away from the males, who tried to marry her despite the fact that she was only 13. After getting lost in a forest, she lost her beast and only friend in the game. Kirito rescued her, and helped her as she resembled his sister. She gained feelings for him, but once she realized his skills, she realized that they could never be together in the game.
Sachi (サチ) Voiced by: Saori Hayami
She was a member of "Black Cats of the Full Moon" which was the first guild Kirito joined. Kirito was especially attached to her. However she died along with the majority of her guild members which led to Kirito wallowing in despair and self-loathing until he read the time delayed message she left for Kirito.