A young and cheerful girl with long black hair who looks no older than 10 years old. Kirito and Asuna found her in a forest in the 22nd floor of Aincrad. After taking care of her, she appears to have lost her memory. She calls Kirito and Asuna "Papa" and "Mama" due to having trouble pronouncing their names which is a side effect of the memory loss. They decided that they would go and search for her friends in the Starting City. Her true identity is actually a players' self-regulation program for mental maintenance, Mental Health Counseling Program or MHCP. After being forbidden by the GM Kayaba Akihiko to come close to the players at the beginning of the death game, she was flooded with errors and broke down. In the process she became an AI that possesses actual intelligence. When the Cardinal system governing SAO decided to erase her, Kirito turned her into a tear shaped crystal pendant. He actually converted her to a part of environmental data for the client program and was saved to his NERvGear's local memory. In ALO, she was able to return to her normal form because ALO was based on a copy of the SAO server. She supports Kirito there as a Navigation Pixie. Kirito and Asuna still treat her as their daughter.
He is a wolfman and the last wolfman of his kind.
Originally selected by Asuna's father to marry Asuna, he was adopted into her family on her father's wishes. He attended the same school with Kayaba Akihiko, who he viewed as a rival. During the Sword Art Online incident, he took advantage of the chaos to steal test subjects for research along with Asuna. In ALfheim Online he adopts the persona of Fairy King Oberon. As the Fairy King Oberon, he keeps Asuna locked up in a bird cage at the top of the World Tree. In the real world, he confronts the powerless Kazuto by voicing his intentions of wedding the unconscious Asuna. While keeping Asuna locked up in ALO, he constantly visited her just to fool around with her. From his actions, one could say that he is a pervert. After Kirito manages to ascend the World Tree, Oberon and Kirito have a devastating fight. By using his system commands, Oberon is able to completely dominate Kirito. Fortunately, Kayaba Akihiko saves Kirito by overriding Oberon's authority. Then, in the real world, Sugou attempts to kill Kirito when he is running to Asuna's hospital. This backfired and ended up with him going to prison. (Source: swordartonline.wikia)
An online game character who appeared in episodes 121-122. It's revealed he was Hasegawa Taizou in the virtual world.
Leader of the Sylph race and an exceptional swordswoman. She was elected as the leader of the Sylph race by popular vote (80% voice of the vote). Her statistics are not very high due to her status as a Lord not allowing her to do much training. Despite her low stats, she is a formidable opponent in the Sylph dueling tournaments. During a meeting with the Cait Sith, she is attacked by Salamanders led by General Eugene. At the same moment, Kirito flies in to challenge the intruder to a duel. After Kirito wins the battle, she attempts to seduce him along with Alicia Rue. Lyfa smothers their attempt, saying that he is accompanying her to the World Tree. At the end of the arc, Lady Sakuya leads a combined force of Cait Sith and Sylph against the World Tree in an attempt to aid Kirito along his journey. (Source: Sword Art Online Wikia)
It is later revealed that her real name is Kanzaki Erza (神崎 エルザ).
He is the owner of the unique skill "Holy Sword" and is considered to be strongest player in-game. He wields the one-handed sword and a tower shield collectively called as Liberator. He also was able to hold off the boss of the fiftieth level for ten minutes by himself, which earned him the title "Man of Legend". It is also rumored in SAO that Heathcliff's health has never gone into the yellow zone. Heathcliff is the creator of Sword Art Online, Kayaba Akihiko, and the final boss on the hundredth floor. This is revealed on floor 75, where he and Kirito have a duel to decide the fate of the players. (Source: swordartonline.wikia)