Sword Art Online

Sword Art Online (SAO) is a Virtual Reality Massively Multiplayer Online Role-Playing Game (VRMMORPG), released in 2022. With the Nerve Gear, a virtual reality helmet that stimulates the user's five senses via their brain, players can experience and control their in-game characters with their minds.

On November 6, 2022, the players log into SAO for the first time, and later discover that they are unable to log out. They are then informed by Akihiko Kayaba, SAO's creator, that if they wish to be free, they must reach the 100th floor of the game's tower and defeat the final boss. However, if their avatars die in-game, their bodies will also die in the real world. One of these players is Kazuto "Kirito" Kirigaya, who was chosen as one of the 1,000 beta testers in the closed beta. Since he had previous experience and knowledge of the game, he felt that he could beat the game easily. As a result, he set out to beat the game on his own. As the game progresses for two years, Kirito eventually befriends a female player named Asuna with whom he ultimately falls in love. After the duo discover the identity of Kayaba's avatar in SAO, they confront and destroy him, freeing themselves and the other players from the game.

Upon being sent back to the real world, Kirito learns that 300 SAO players, including Asuna, still have not awakened yet. Following a clue about Asuna's whereabouts in another VRMMORPG called Alfheim Online (ALO), Kirito also enters the ALO's mainframe. Helped by his cousin Suguha Kirigaya, known as Leafa in the game, he learns that the trapped players in ALO are part of a plan conceived by Nobuyuki Sugō to perform illegal experiments on their minds to put them under his control, including Asuna, whom he intends to marry in the real world in order to take over her family's company. After Kirito foils Nobuyuki's plans, he finally reunites with Asuna back in the real world.

Soon after, Kirito plays another game called Gun Gale Online (GGO) to investigate the mysterious connection between it and deaths occurring in the real world. Assisted by a female player he meets in the game called Sinon, he identifies and exposes the culprits, who include some former members of a murderous guild he previously encountered in SAO.

Kirito is later recruited to assist in testing a state-of-the-art FullDive machine, Soul Translator (STL), which has an interface that is far more realistic and complex than the previous machine he had played. He tests the STL by entering a Virtual Reality world created with The Seed package, named UnderWorld (UW). In the UW mainframe, the flow of time proceeds a thousand times faster than in the real world, and Kirito's memories of what happens inside are restricted. However, he is attacked by one of the murderers from GGO and wakes up inside UnderWorld, leaving him unable to remember how he ended up there or to log out, with his real self left in a comatose state