Nobuyuki Sugou

Nobuyuki Sugou is the main antagonist of the Fairy Dance Arc in the light novel/anime/manga series Sword Art Online. He also is Asuna's ex-fiance, the former director of RECTO Progress Inc, the ruler of ALfheim online as Fairy King Oberon and Kazuto/Kirito's arch-nemesis.

He was voiced by Takehito Koyasu in the Japanese version, and Todd Haberkorn in the English dubbed version.

Real Life
In the real world, Sugou has short dark brown hair, dark eyes and glasses, and wears a business suit. He is fairly tall, and has a red tie. Later, during his fight with Kirito, his right eye becomes swollen and engorged, turning into a pinkish hue with bloodshot veins.

ALfheim Online Avatar
Sugou's ALO avatar as the Fairy King, Oberon. In ALO, his avatar has green eyes and wings, shoulder length blonde hair, and wears a crown, long dark green robe and green cloak, both with an emerald-like jewel. In both cases, he has pale skin, and in ALO, he has long pointed ears, as do all the characters except Cait Siths, but his have gold leaves on top of them, like Asuna's avatar during the Fairy Dance arc.

Personality
Sugou is an extremely cruel, callous, arrogant, sadistic, ruthless, and deranged psychopath who wants nothing more than to become a god amongst all living things, whether in the digital world or not. In addition, he also has a very perverted and depraved mind, as he gleefully raped Asuna in front of Kirito. However, he usually hides these traits beneath a polite, calm, and soft-spoken manner, and rarely loses his temper, though whenever he does, he becomes violent and aggressive, especially during his fight with Kirito. He is deceitful and manipulative, and has high intelligence that helps him outside his avatar and in.

History
Originally selected by Asuna's father to marry Asuna, he was soon adopted into her family on her father's wishes. He attended the same school with Kayaba Akihiko, who he viewed as his rival. Once Sword Art Online was cleared (until that point the SAO servers were untouchable), he was able to hack into SAO server via router and obtain the minds of 300 SAO players (including Asuna) as test subjects for his research on controlling peoples' feelings and memories; in other words, research on the manipulation of the human soul. In ALfheim Online he then adopts the persona of Fairy King Oberon.

As the Fairy King Oberon, Sugou kept Asuna locked up in a bird cage at the top of the World Tree. In the real world, he confronted the powerless Kazuto by voicing his intentions of wedding the unconscious Asuna. While keeping Asuna locked up in ALO, he constantly visited her, and there he brought her to the verge of tears by harassing her and making her aware that he held full control over this virtual world.

After Kirito managed to ascend the World Tree and reach Asuna, Oberon appeared and used his administrator privileges to keep Kirito pinned down with powerful gravity magic. Once Kirito and Asuna were unable to move due to the gravity magic, he manipulated a menu to call down 2 chains, which he used to shackle Asuna. After Kirito voiced his protest against Oberon mistreating Asuna, Oberon used Kirito's sword to stab him, soon afterwards turning the pain absorber program level down so that Kirito would experience real pain from the injury. Oberon then began sexually assaulting Asuna in front of the helpless Kirito. Fortunately, Kayaba Akihiko saved Kirito by giving him the details necessary to log in with Kayaba's ID Heathcliff, which, due to ALO being a exact copy of the SAO servers, had greater system authority than Oberon's ID. This allowed Kirito to use a Voice Command to nullify Oberon's supervisor authority.

After this, Oberon tried using a Voice Command to generate Excaliber, the strongest weapon in ALO, for himself but to no avail. After Kirito repeated the same command and gave the generated Excaliber to Oberon, he used another Voice Command to set the pain absorber program to level 0, causing every injury to feel as if it was 100% real. Even though Oberon tried attacking Kirito, however due to his rage and lack of experience, Oberon left an easy opening, which Kirito used to strike Oberon at his cheek. Afterwards, Kirito lashed out at Oberon with all the anger he had accumulated, amputating his hand, bisecting him, and then finally stabbing his sword though his eye, killing his avatar.

Afterwards, in the real world, Sugou attempted to kill Kazuto with a knife when he was running to Asuna's hospital. Even though he was in control of the situation for a little while and even had the chance to deal a fatal blow, but due to the pain of his eye (which was stabbed in ALO with level 0 pain absorption), he missed. Kazuto then mustered the strength needed to overpower him. Kirito then proceeded to pick up said knife and pointed out that despite the weapon having not real weight or length, he could easily kill Sugou with it. Sugou then attempts to run for his life only to have his head slammed into a car with enough force to leave an indent. As Kirito thinks of all the things Sugou had done to Asuna, Kirito is tempted for a moment to kill Sugou, only to decide he did not have the right and he should let the law decide his fate. Eventually, Sugou was sent to prison, where he attempted to pin the blame onto Kayaba, but after an employee of his revealed Sugou's plot, he confessed to his crimes and revealed the full extent of his plans to the world, which leads to the downfall of RECTO Progress Inc.

Trivia

 * Sugou's ALO avatar "Oberon" is based on a fictional character with the same name who is the king of the fairies in medieval and Renaissance literature. He is best known as a character in William Shakespeare's play A Midsummer Night's Dream, in which he is Consort to Titania, Queen of the Fairies.
 * Sugou appears in Sword Art Online: Infinity Moment as Alberich.