Personality
Kirito is someone who is not good with words, as said by Klein, and can be quite direct. This is due to him not having many friends and closing others off because of his love for computers. As such, he can come off as a rude person to others, such as Lisbeth and Sinon. Sometimes, he actually seems to enjoy angering and teasing people as well. Also, from time to time, Kirito can be quite overconfident thinking he can do things others can not.

He is almost always a calm and collected character, rarely showing any signs of distress. When Kayaba Akihiko appeared in SAO and announced that it had become a Death Game, Kirito showed only a slight reaction and was able to quickly accept the new conditions of the game, while many others panicked. He has shown different moods throughout the series; at times being rather cheerful, while being gloomy at others. When in a battle, he becomes incredibly fierce and aggressive. Sometimes, his fierceness is up to the point where he loses control of himself and is even unable to recall what he had done.

However, Kirito is actually a kind person who is just misunderstood. Despite the general population opinion towards beta testers in SAO, he refused to abandon another player in trouble. This is only strengthened after the demise of the Moonlit Black Cats. He also comforts others who are scared or down such as Silica after she lost Pina. He claims to help some female players in SAO because they remind him of his sister, whom he feels to have forced into kendo and feels guilty for that. These kind of acts have earned him respect and affection from many girls. Kirito, unlike usual male heroes, is not very dense as he was able to tell that Lisbeth was going to confess to him before Asuna interrupted them.