Sword Art Online: Calibur

ソードアート・オンライン キャリバー

Prequel

manga
2014
Publishers:
Kirito and Sinon's battle with Death Gun is over, but mere weeks later, something strange is afoot in the next-generation VRMMO ALfheim Online. A new duelist with a custom sword skill is defeating all comers--including Kirito! But when Asuna goes to face this duelist, she receives something she never expected: an invitation to an exclusive guild! But what is their aim? The Mother's Rosario arc begins! Note: Covers the Mother's Rosario Arc from Volume 7 of the light novel series. (Source: Yen Press)

Sequel

manga
2016
Publishers:
Kirito awakens in a vast, fantastical forest filled with towering trees. In his search for clues to the truth of his surroundings, he encounters a young boy who seems to know him. He ought to be a simple NPC, but the depth of his emotions seem no different than a human. As they search for the boy's parents, Kirito finds a peculiar memory returning to him. A memory from his own childhood, of this boy and a girl, too, with golden hair, and a name he should have never forgotten—Alice. (Source: Yen Press)

Adaptation

novel
2009
Publishers:
**Read the novel that ignited the phenomenon!** In the year 2022, gamers rejoice as Sword Art Online - a VRMMORPG (Virtual Reality Massively Multiplayer Online Role Playing Game) like no other - debuts, allowing players to take full advantage of the ultimate in gaming technology: NerveGear, a system that allows users to completely immerse themselves in a wholly realistic gaming experience. But when the game goes live, the elation of the players quickly turns to horror as they discover that, for all its amazing features, SAO is missing one of the most basic functions of any MMORPG - a log-out button. Now trapped in the virtual world of Aincrad, their bodies held captive by NerveGear in the real world, users are issued a chilling ultimatum: conquer all one hundred floors of Aincrad to regain your freedom. But in the warped world of SAO, “game over” means certain death - both virtual and real… *Source: Yen Press, Vol. 1*

Alternative

novel
2011
The alternative version to the Caliber SS in volume 8, where they decided not to save Freya in the dungeon. The SS in the title means 少し失敗 (sukoshi shippai) which translates to Slight Failure.