Aincrad

Aincrad (アインクラッド) is the first «Realized World» shown in the «Sword Art Online» light novel series. Its full name is An Incarnating Radius (アン・インカーネイティング・ラディウス).

Background
Aincrad is the world set as the stage for «Sword Art Online», declared to be the world's first VRMMORPG in history. It was incorporated in «ALfheim Online» on May 2025.

The base currency of Aincrad is the Col.

Etymology and Meaning
A «Realized World» called " A n Inc arnating Rad ius;" the name has been abbreviated as Aincrad. It is also inferable that its design is symbolic for time and space. The vertical axis represents the time and the circular floors represent the space.

Geography
Aincrad is an iron-and-stone made floating castle that has about ten kilometers floor base diameter and consists of a hundred floors stacking straight upwards, meaning that each floor's diameter is a bit smaller than the previous one. On each floor, there are a couple of large cities along with countless small scale towns and villages, forests, plains, and even lakes. Only one stairway links each floor to another, and the stairways exists beyond the boss room of each dungeon. The «Teleport Gates» of every unlocked cities are connected to one another.

Known Monsters

 * Ant Queen (46th Floor)
 * Blue Slug
 * Dark Elf (3rd Floor)
 * Demonic Servant (74th Floor - Labyrinth)
 * Drunken Apes (35th Floor)
 * Dusk Lizard
 * Elder Treant (3rd Floor)
 * Feathery Dragon (Pina)
 * Mandrake (47th Floor)
 * Walking Flower
 * Forest Elf (3rd Floor)
 * Four Eyed Frog (1st Floor)
 * Frenzy Boar (Level 1) (1st Floor)
 * Frost Bone (55th Floor)
 * Frost Dragon (55th Floor)
 * Gargoyle (27th Floor)
 * Giant Venus Fly Trap (47th Floor)
 * Jagged Worm
 * Killer Mantis (20th Floor)
 * Land Anemone (47th Floor)
 * Large Nepent
 * Little Nepent (Level 3) (1st Floor)
 * Lizardman Lord (Level 82) (74th Floor - Labyrinth)
 * Lungfish (22nd Floor - event monster)
 * Pup (28th Floor)
 * Ragout Rabbit (Super Rare) (74th Floor)
 * Ruin Kobold Sentinel (1st Floor)
 * Ruin Kobold Trooper (1st Floor - Labyrinth)
 * Storm Hornet (2nd Floor)
 * Treant Sapling (3rd Floor)
 * Trembling Cow (2nd Floor)
 * Trembling Ox (2nd Floor)
 * Werelion (40th Floor)
 * Werepanther (22nd Floor - quest area)
 * Wind Wasp (2nd Floor)
 * Wolf (1st Floor)

Known Plants

 * Pneuma Flower

New Aincrad (ALO Version)
At the end of Fairy Dance Arc (ALfheim Online), with the sprouting of the «World Seed», some of the old ALO players funded a new company, Ymir, which bought all of the ALO data from RECTO Progress Inc. for a small fee and discovered that a complete copy of the castle existed on the server. As the company had to fight a decrease in the playerbase due to RECTO Progress' inhuman experiments and because the company was formed by veteran MMO players who had been playing since the 2D age and couldn't bear the deletion of the intricately designed castle, the castle of New Aincrad was implemented into the ALO world on May 2025. The castle is essentially identical to the original Aincrad, except for a few key features.

First, the bosses and dungeon monsters were made significantly more difficult, as there is no threat of real death in the ALO's Aincrad. Dungeon maps, bosses, and similar features were likely re-done, as the Clearers in ALO continue to utilize mapping and scouting strategies on bosses. The last known change is on the Monument of Life. After this update, the monument, which before used to list existing players who were still alive at the time, is now called as the «Monument of Swordsmen» and is used to list players who participate in clearing the boss of each floor. As the monument can only record 7 player names for each floor cleared at most (due to space limitations), if more than 1 party participates in the battle against the boss of the floor, only the name of the leader of each party will be listed on the monument, however, if 1 party of up to 7 players is able to beat the boss on their own, the name of each member of the party will appear on the monument.

Since Aincrad was fused with ALfheim Online's gameplay, the system was also designed to re-account for magic, flying, and the new limitations and additions with Sword Skills. It is now possible to fly from floor to floor in ALO's Aincrad, though there is an invisible wall at the highest front line floor, preventing access via flight to floors that have not yet been unlocked. Dungeons are no-flying zones, and the remain-light system was incorporated from ALO.

It is currently being cleared by guilds and the like, led by high-level players like General Eugene.