Yamato

Yamato is an alpha tester for Sword Art Online, and is the main protagonist of Sword Art Online: Last Light, and an antagonist/deuteragonist of Sword Art Online: Clashing Blades.

Appearance
Yamato wears a black longsleeve undershirt with black pants and dark brown padded boots that reach up to his knees for leg protection. He wears two black fingerless gloves and a long white haiori with black edge and trim.

Background
Next to nothing is known about Yamato's background, as he never tells anyone about who he is in the real world.

It was revealed by Kirei Kyosho that Yamato was his student at his school of kenjutsu, and that Yamato was his best student. Yamato also trained with Kirei for a time after they were trapped in a game, but eventually left to be on his own.

Personality
Although almost completely uncaring about others and relishing in a good fight, Yamato isn't a Player Killer who goes out of his way to defeat other players. He kills players who he sees as worthy adversaries, and will challenge said player to a fight (the exception being Ishi, whom Yamato attacked without warning). Yamato's unpredictable nature and PKing tendencies leads him to work completely alone, wandering aimlessly around the world of Sword Art Online.

He has been noted as caring only about fighting in and of itself and not much else.

Relationships
Ishi

Yamato holds Ishi in high regard, noting his combat skill as the best he's seen of any other player in Sword Art Online. He sees Ishi as the only one who has a chance in being able to defeat him, and secretly guides him to become stronger and stronger until he's ready to take him head on in a full fight.

Sakura 

It was revealed by Sakura to Ishi that the two were childhood friends. It is also said that both Sakura and Yamato fell in love with each other. It was never taken to a full relationship however, because Yamato wished to protect Sakura from everything he had to face in the future, leading to him leaving her and Sakura retreating to live with her grandfather and brother for the rest of the game.

Majora

Yamato's closest friend turned greatest enemy, Majora betrayed Yamato to Laughing Coffin for his own benefit, expecting Yamato to die at their hands so he would not be held back by Yamato's superior skills any longer. Yamato survived, and had since swore to hunt down and kill his former friend.

Kamui

Yamato has had a few run-ins with Kamui during the latter's hunt for Skeith, with each encounter leading to a battle between the two. Yamato and Kamui proved to be evenly matched with each other for a time, but in the end, Yamato was able to prove himself as the better swordsman. Kamui curses Yamato to this day.

Abilities
Yamato is an unmatched swordsman, having mastered the use of his personal katana, Kusanagi. His strikes are quick, precise, and almost always lethal, having such prowess in his art that he can make it appear as though he hadn't unsheathed his sword at all. His swift and graceful combat style is renown across SAO as an unbeatable technique, as near all who has fought against it are now dead. He is able to use an ability known as Judgement Cut to cut through enemies at range with extremely powerful and deadly slashes. Taking his katana in hand, he unsheathes his sword at blinding speed multiple times to cut into enemies at range, causing exponential damage.

Yamato has one of the quickest reaction times in SAO, to the point where it could almost be considered clairvoyant, and was originally chosen to recieve the Dual Blades skill. This was eventually dropped when Yamato acquired Corbenik, at this point being deemed too dangerous to recieve such a skill.

Yamato also possesses the quickest sword hand of all players in Sword Art Online, having such speed with his blade that most of the time his sword is rarely seen at all in combat. However, his overall speed is surpassed by Ishi.

Over less than a year after the game's release, Yamato had already climbed to legendary status as the deadliest Player Killer in Sword Art Online.

Trivia

 * The name Yamato Ovan is based on the sword Yamato wielded by Vergil, featured in the Devil May Cry series, while Ovan is derived from the character Ovan, a player of The World R:2 and the opposite of Haseo, who shares his name with Ishi's surname.
 * The Judgement Cut ability is based on the skill of the same name used by Vergil with Yamato.