PoH (no angel himself): I know it's your favorite but last time we did that you killed the winner anyway.
Johnny Black: Oh come on! You spoiled it! It's no fun if they know they're gonna die!
Entries are where the character had the most impact.
- "Fairy Dance" arc: Nobuyuki Sugou/Oberon the Fairy King is the director of research and development at RECT Progress Incorporated, former classmate—and the one-time fiancée—of Asuna Yuuki. Obsessed with research into the manipulation of human emotion and envious of his classmate Akihiko Kayaba. Following the clearing of Sword Art Online, Sugou trapped 300 of the surviving players in his own game, Alfheim Online, where he ran experiments on their minds, testing their fear and pain responses. Kidnapping Asuna in the game, he keeps her trapped in a gilded cage at the top of Alfheim's World Tree, while plotting to wed the comatose girl in the real world. When Kirito reaches the top of the World Tree, Sugou uses his administrator abilities to paralyze him, tortures him, and then sexually assaults Asuna in front of him, gloating the entire time about how, once he's freed, he will rape her again in real life. When he fails, he attempts to kill Kirito in the real world, attacking him with a knife. Mentioned again in Alicization, it is shown that Sugou put spies inside the Ocean Turtle with the intention of selling their A.I.s to foreign governments as he wanted to do with the results of his own experiments. A megalomaniac obsessed with his own glory, Sugou lack any of the virtues of his former classmates.
- "Phantom Bullet" arc:
- Shoichi Shinkawa/Red Eyed XaXa is one of the top members of the Laughing Coffin guild in SAO, and the guild's Master Swordsman. During the Murder Investigation Arc in SAO, XaXa, alongside PoH and Johnny Black, ambushed and attempted to murder players Caynz, Yolko, and Schmitt; when Kirito intervened, the trio also tried to kill him. After making his way back to the real world, XaXa, bored and seeking a way to kill again, took advantage of his younger brother Kyoji's fragile mental state, to convince Kyoji to create the online persona of Sterben/Death Gun in Gun Gale Online, ultimately hijacking Kyoji's desire to be "the strongest" for his own ends. Using Kyoji, and his old partner Johnny Black as aides, XaXa was able to arrange the murders of players Tamotsu Shigemura/XeXeed, Tarako Usujio, Pale Rider, and Garret, before sending Kyoji to murder his own crush, Shino Asada. A sadist at heart, XaXa makes a point of crippling his opponents' avatars with a paralyzing toxin before delivering the coup de grace, and during his sword fight with Kirito in GGO does his best to cut him to ribbons, mocking him the entire time.
- Atsushi Kanamoto/Johnny Black is another top member of the Laughing Coffin guild. As the guild's Master Poisoner, Johnny came up with a way to paralyze opponents so that they could then be tortured to death, and puts this poison into effect during his, XaXa, and PoH's attack on the members of the Golden Apple guild. When discussing what they will do with the captured trio, Johnny expresses a desire to make them fight each other to the death, promising to release the survivor; when PoH notes that Johnny will just kill the survivor, Johnny complains about how the Guild Leader has ruined the surprise. He subsequently tries to poison Kirito when he comes to the Golden Apple trio's rescue. Escaping into the real world, Johnny was recruited by XaXa during the Death Gun murders, poisoning Pale Rider and Garret in their homes, before again making a getaway. He was finally arrested when, after having lain in wait for six months, he attacked Kirito and Asuna on the street, intending to inject them with poison from a syringe, and hospitalizing Kirito.
- "Alicization" arc:
- Quinella rules the Underworld as the High Minister of the Axiom Church. In an effort to obtain immortality, she fuses herself with the Cardinal System of the Underworld, calls herself a goddess, and begins corrupting the souls of the Underworld nobility by spreading ignorance and fear among the populace. She also brainwashes every rebel fighting against her government and the Champions of the Four Empires Unity Tournament—something which she had done for centuries while also performing fatal experiments on children. After realizing the invasion of the Dark Territory is inevitable, Quinella confiscates every line of defense from the Human Empire to make the people more dependent on the Axiom Church. She transforms the loyal Integrity Knights' loved ones into swords and forms a Golem out of them, making them believe they are protecting their loved ones while feeling constant agony to protect "her" empire. Said empire is so bad that both Kirito and Cardinal feel that destroying the Underworld would be better than having Quinella rule it.
- Gabriel Miller, murderous even as a child, is the boss of Glowgen Defense Systems and leads the raid to the Ocean Turtle on behalf of the NSA. He enters into the Underworld in the super-account of Vecta, God of Darkness, intending on stealing the only fully-developed Artificial Fluctlight. With his new powers, Gabriel turns the turbulent Seven Lords Assembly of the Dark Territory—whose inhabitants are forced to follow the "rule of the strongest"—into his dictatorship. He starts a brutal invasion of the Human Empire wherein he uses strategies that cause unnecessary deaths on his own side and uses members of his own army as Demihuman sacrifices to empower his sorceress. Contacting his allies in the Real World, Gabriel summons thousands of unaware players to kill AIs while believing that they were inside just another game, even letting them kill Dark Territory forces. Defined by his megalomania and cruelty, Gabriel goes so far as to think of the possibility of destroying the Underworld and killing every AI in it after his victory.
- Vassago Casals, aka PoH—Prince of Hell—enters SAO to kill a target, later founding the Laughing Coffin guild, where he rallies together the worst of those trapped in the game and has them slaughter their fellow players, simply for the sheer joy that Vassago takes in seeing East Asians kill each other. Later betraying his own guild and abandoning it to die, Vassago corrupts other players and sends them to kill those who had participated in the Laughing Coffin's downfall. Vassago later returns as a member of Glowgen Defence Systems, becoming Gabriel Miller's right-hand man and leading Gabriel's invasion of the Human Territory. When Japanese players appear to try to contain the invasion, Vassago contacts unaware players from China and Korea, lies to them about the situation, and connects them to the Underworld. After finding a comatose Kirito, Vassago tortures him and promises to torture his loved ones to death and kill everything else in the Underworld.
- Dee Eye Ell is the leader of the Dark Mage guild who wants to become a second Administrator and whose desires to take control of the Dark Territory were interrupted by the arrival of Dark God Vecta, after which she becomes one of his generals. She orders the release of all 800 Minions to attack the enemy, knowing that they will kill her Demihuman allies, whom she despises. When her plans to use the spatial resources from the dead militia fail, Vecta suggests the sacrifice of 3,000 orcs to recharge energy, which she cheerfully carries out. When under attack, Dee Eye Ell murders her own subordinates to drain their life to save herself. When she detects Leafa's arrival, Dee Eye Ell drains her energy in an excruciatingly painful process, during which the anime depicts her usage of tentacles as rape. When the orc leader Lilpilin protests, Dee Eye Ell proceeds to insult his species and tries to kill him before dying at Leafa's hands, unable to understand why a human would save a orc.
- Progressive: In this retelling of the "Aincrad" arc, Morte is one of the thousands of players trapped in SAO and the first murderer inside it. Superficially jolly, Morte convinces a desperate player to scam other players and steal their weapons before trying to get him executed for said crime. Reaching the next floor, Morte enjoys killing a likely sentient NPC and manipulates the two biggest guilds of players into fighting each other while he challenges Kirito to a seemingly non-lethal duel, trying to kill him with a Finishing Move and make it look like an accident as he had done to others in the past. The first murderer inside SAO—managing to get people killed despite the heavy restrictions at the time—Morte become the predecessor to the Laughing Coffin guild members.
- Infinity Moment/Hollow Fragment: Nobuyuki Sugou is even worse than in canon. When attempting to hack SAO to acquire test subjects, Sugou is pulled into the death game himself. Finding himself with admin privileges, he creates an overpowered avatar for himself named Alberich. He attempts to join the Assault Team to pose as a hero, but gets rejected for being Unskilled, but Strong, at which point he continues with his twisted experiments on various players to change their emotional states. Due to his GM powers allowing him to bypass the Harassment Code, he is also believed to be behind a string of sexual assaults on female players. He then appears before the Assault Team, paralyzing them and unleashes the intended Final Boss of SAO to kill them all, so that he can pose as the only survivor and the hero who saved the day. When this doesn't work, he attempts to use a special sword to finish the job himself.