According to legend, in the long-distant past, there was a world called The Ground, with the huge Uniel Continent at its center.In that world, the forest elven kingdom Kales'Oh,the dark elven kingdom Lyusula,the human Alliance of the Nine kingdoms, the underground realm of the dwarves, and various other nations and races were established. While there were skirmishes at times, the land was at peace.

But one day, a hundred varied regions from around the world were cut into circles from the earth and summoned up to the sky. The circles were under three kilometers across at the smallest and over ten kilometers at the largest. They were stacked in a conical formation to form a gigantic floating fortress a hundred floors tall.After the Great Separation,the civilizations left behind on The Ground declined, becoming small villages, barely surviving.

The castle held its countless towns and villages, mountains, forests and lakes, and never again returned to earth. The magic powers that caused the old civilization to flourish were lost, and with them, the nine kingdoms of man. This is known as The «Forfeiture». The production means and technologies for long-ranged projectiles or bows in other words were lost for eternity as well in The «Forfeiture». As such, Aincrad lacked skills like Bowcraft or Archery. Most towns reverted to maintaining themselves, and the floors lost contact with one another. A great length of time passed. Legends and tales of the Great Separation still existed among the two elf races, the only people to keep their kingdoms intact from that fateful time.

Kirito The BackSwordman

Kazuto is someone who is not good with words.This is due to him not having many friends and closing others off because of his love for computers.Thus, he can appear to be rude to others.Sometimes, he actually seems to enjoy angering and teasing people.Also, from time to time, Kazuto can be quite overconfident thinking he can do things others cannot.Kazuto is almost always a calm and collected character, rarely showing any signs of distress. However, Kazuto is actually a kind person, willing to sacrifice himself to help others. Kazuto is also a very emotional person and lets his emotions control him from time to time. Kazuto is a person with incredibly strong resolve, willing to do anything and everything in his power to accomplish something that is important to him without any hesitation.

Asuna The Flash

Asuna is a kind and helpful young woman. Asuna is also somewhat proud and despite her kind personality, she will not hesitate to get physical with those that challenge her authority or make fun of her abilities, such as cooking.Asuna, in a similar manner to Kirito, is someone who can be controlled and manipulated by her emotions.Asuna lived a comfortable life in her large home in Setagaya with her mother, father, and her brother.She originally went to private,all-girl schools.Asuna used her brother's NerveGear. Then she was suddenly trapped along with all the other people who happened to be in the NerveGear at that moment. Determined to return home, she joined the Blood Knights.

Silica The The Daughter of the Dragons

Keiko is the bastard daughter of Alicia Ayano and an unknown man. Alicia cheated on her husband. After both men left Alicia, she raised Keiko alone. Irritable and abusive, she treated Keiko like trash.At some point, Keiko couldn't take it anymore, she took a knife and killed her mother. Then she ran until she fell next to an abandoned warehouse. She went inside to hide when she saw a huge gate. Without thinking, she went inside and appeared in the 55th Floor.In the city named Granzam, Keiko was alone and afraid, wandering the streets until she rescued a little dragon from a cage and they became friends. Keiko named the female dragon Pina. Pina is a «Feathered Little Dragon» with its blue body covered in soft, pale blue feathers and two long feathers instead of a tail.

Klein The Bandit

Klein is an arrogant, self-confident womanizer. He is smart and cunning, he likes alcohol, women and fights. He is often called "the modern-day Jenkins Khan". Klein founded a gang of misfit criminals and thieves. Regardless of the fact that he is trapped in this world, he wants to become rich, get glory and women.

Heathcliff

Heathcliff, the leader of the blood knights, is said to be the best gladiator in all of Aincrad. In addition, he is politically astute and a good tactician.

Lisbeth The Blacksmith

Lisbeth is a very friendly person that can get along with just about everyone she meets. She is hardworking and takes great pride in her abilities as a blacksmith. She will become very defensive and aggressive if someone were to challenge her pride as a blacksmith much.She has a bad temper and can get somewhat violent. Lisbeth is very teasing as well.

Nautilus The Broken

Nautilus was discribed by Asuna as a bit of a coward, this was mostly accurate do Eiji’s tend to freeze up when ever he encountered a situation that he couldn’t handle.

Dragon Dogma is the mysterious leader of the Divine Dragons Alliance, the largest guild in Aincrad. Nothing is known about him, but rumors say he wears a dragon's head as a helmet, is very tall, and has muscular build.It is said that he is a great leader as his decisions made the Divine Dragons Alliance what it is today. No one knows what gender he is or the sound of his voice as he speaks in a heavy, commanding false voice.

PoH is a sadistic assassin who enjoys killing. He is the founder of the Laughing Coffins, the largest guild of assassins in Aincrad. He is an extremely intelligent and skilled assassin, he has built a fearsome reputation and no one wants to be on his list.

The largest guilds in the world of Aincrad

1.Divine Dragons Alliance=Divine Dragons Alliance is the largest guild in Aincrad. They are enemies of both the Blood Knights and the Laughing Coffin. They have the advantage of using dragons. Thus, they have dominance in the air.

2. Knights of the Blood=is the second largest guild in Aincrad after the Divine Dragons Alliance. They are distinguished for their discipline and for the fact that most of the guild members are humans who are in Aincrad and not Avatars (like Asuna).Their goal is to take control of all of Aincrad and bring order. They have the advantage that Kayaba is helping them from behind the scenes.Heathcliff, the leader of the blood knights, is said to be the best gladiator in all of Aincrad. In addition, he is politically astute and a good tactician.

3.Golden Apple=Golden Apple is an unaffiliated guild that focuses on trade, the sale of weapons and services, and the flow of information in exchange for a fee. It is the third largest guild in Aincrad after the Blood Knights and the Divine Dragons Alliance.

4.Laughing Coffin=Laughing Coffin is an assassin's guild founded by PoH. The Guild makes contracts with people and kills for a fee. It is the most terrifying guild in all of Aincrad as they do not hesitate to murder anyone they have a target for.

5.Aincrad Liberation Force=Aincrad Liberation Force It was the largest guild of adventurers in Aincrad with over 3000 adventurers with a clear hierarchy. With Kibaou as its leader, the guild flourished for a while but then began to decline as new conflicts began. It finally collapsed during the battle on the 25th floor. It was forced to compete with another guild and is now a shadow of its former self.

6.Fuurinkazan=Fuurinkazan is the name of Klein's gang. It is famous throughout Aincrad as a criminal organization specializing in stealing valuable objects.

7.Titan's Hand=It is an assassination guild much smaller than the Laughing Coffin. Rosalia, the leader of the guild, is independent and a kind of enemy to lovers with Klein. Rosalia is cunning and intelligent but also quite hot-tempered.