Kayaba Akihiko (茅場晶彦) is the development director and Game Master (GM) of the VRMMORPG Sword Art Online. The designer of the NerveGear, the Cardinal System, and the World Seed.

The founder of the Knights of the Blood guild in SAO, owner of the first Unique Skill, "Holy Sword", he was considered to be the strongest player. Had the sword-and-shield equipment set called Liberator. Kept facing the Floor 50 boss alone for ten minutes, earning the title of the Man of Legend. His hit points famously never reached the yellow zone, which means below half damage.

The main antagonist of the Aincrad Arc 1/2. Mentioned in the Fairy Dance Arc 1/2 and Alicization Arc 1/2.

Bio

Real Life Description	Fine and sharp facial features; metal-like eyes and short hair. Wore a white shirt and necktie, a lab coat.
Age	28 (End of Aincrad Arc)
Birthdate	1995-1996
Gender	Male
Family	Kōjiro Rinko (love interest)
VR/AR	Sword Art Online
Nickname in SAO	Heathcliff (ヒースクリフ hīsukurifu)
Epithets	The Strongest Man, The Living Legend, The Paladin
Affiliation	Knights of Blood (SAO)
Occupation	Game Designer for Argus; Guild Leader (SAO); 100th Floor Boss (SAO)
Voice Actors	JP: Yamadera Koichi, Ōkawa Tōru (Heathcliff); EN: Marc Diraison, Kevin M. Connolly (Heathcliff)
First Appearance	Novel: Volume 1 Chapter 2; Manga: Aincrad Manga Stage.001; Anime: Episode 1; Game: Infinity Moment

SAO Player Character

Kayaba Akihiko's avatar was the only one different from his real-world looks: muscular, tall, physically strong, with steel-gray hair. He wore the guild armor (with the primary and secondary colors reversed) most of the time.

At the official launch day of SAO, Akihiko as GM looked like a faceless cloaked and hooded figure of enormous size.

Personality

Throughout the few times he appeared in SAO, Kayaba Akihiko was calm, soft-spoken, and seemingly distant, although Heathcliff was regarded as just and hearty. After his defeat from Kirito's hand, Akihiko accepted it gracefully. Appearing after the battle with Oberon, he seemed pleased with Kirito's hard-earned victory, and he had helped him in an important way.

Akihiko is a very driven and sincere man; when he talked to Kirito about Aincrad, it was evident he was able to make his dream as a kid, the airborne metal castle, into tangible reality, reality in the true meaning of the word "virtual" — overcoming all the physical, technical, and moral implications.

Indeed, Akihiko has shown to be distant from morals and worries of the others. He was the one who thought of the game world that killed thousands in the few moments after his statement regarding the dark nature of SAO and thousands more as it went on, he pulled the trigger on it trapping ten thousand people for years, and he treated the first deaths with a phrasing amounting to, "Their minds are gone from both worlds." During the last duel, when he ended up striking Asuna instead of Kirito, he seemed amused and not mortified.

Despite his cruelty, Akihiko did his utmost to make SAO a fair world. He was even personally helping his guild to clear the dungeons, although that could be attributed to his vain wish for glory and a pure wish to have fun playing with everyone. He would only go on to officially become the final boss after the players would clear floor 95, but Kirito found him out early. He seemed to really want to see his game beaten, because he had made his own character immortal with a trick that would conceal that truth.

It can be concluded that he was psychopathic and immature, which forms the majority of real-life criminals' mental portraits, but he also had a strong sense of justice, and liked and respected Kirito as a person.

Background

As a child, Kiyaba Akihiko was spending his leisure time reading. He was not an avid gamer, but he was in the Mathematics Club during high school. In university, he was busy working in various laboratories.

When Akihiko began developing SAO, he spent years on programming it. He managed to make Aincrad float just the way he had dreamed of, and had suddenly been left without a dream to go on.

He was in love with Kōjiro Rinko, who had been assisting his game developing efforts for years, and was the one that was taking care of his body during his FullDive into SAO.

Related Sword Art Online Events

Canon

November 6, 2022: Sword Art Online launches, GM explains the situation.
April 23, 2024: Asuna and Kirito invite Heathcliff to discuss a murder within the safe zone. Heathcliff debunks Kirito's theorizing, suggests to sanitize their information sources.
October, 2024: Heathcliff is renowned for being the guild leader who does not really lead but defers judgement on affairs to sub-leaders. He only interferes as Asuna wants to leave the guild, and challenges Kirito to a duel whereupon Kirito loses to a seemingly strange quirk of the game engine and becomes a guild member himself.
November, 2024: After Heathcliff and therefore SAO is beaten, Akihiko wants to be erased as the game erases itself, and reveals that as part of his plan all along. He uses his special FullDive machine to scan his mind and transfer it into the virtual world. His brain cells burn and his body dies.
Fairy Dance Arc: the brain scan had been successful with a chance of 1 to 1000, and Kirito's voice during his fight versus Oberon causes his virtual self's main routine to activate. He then talks to Kirito, who is depressed and about to give up, and reminds Kirito of having won and taught Heathcliff that the willpower prevails over the machine. Kirito stands up to fight, and Akihiko gives him the administrative credentials, which Kirito uses to fix the situation and exact a rather brutal revenge on Sugou Nobuyuki. Akihiko gives Kirito a World Seed to use elsewhere in exchange for the help, then disappears.

Non-canon

Infinity Moment, Hollow Fragment

During the Floor 75 duel with Kirito, a software glitch occurs on Heathcliff's arm, to the both players' surprise. Kirito attacks him again, and more glitches appear on Heathcliff and his equipment, ending with Kirito piercing him with a Dark Repulser and Heathcliff disappearing in a large glitch.

Heathcliff reappears after the defeat of Hollow Strea, congratulates the Clearers, and explains that the glitch was caused by the accumulation of the players' distress — which overloaded the Mental Health Counseling Program Prototype 002, codename Strea, and had repercussions reaching the Cardinal System's core; at the same time, Sugou Nobuyuki's interference diverted the system's resources to a different issue, and Akihiko was called to take administrative action.

Heathcliff declares the game beaten, and brings back the logout button. He and Kirito are about to resume the duel alone in the world, but the other players refuse to leave and want to fight together. Akihiko wonders whether perhaps his real goal in making SAO was to see people unite for a common cause.

Heathcliff is defeated and says he will remain in Aincrad alone following his own rules. He thanks the players for giving him perspective, then vanishes.

In the aftermath, they learn that Akihiko had killed himself by a brain scan soon after the initial duel on Floor 75.

References

Kayaba Akihiko - Fan Wiki