Sword Art Online: Integral Factor

Sword Art Online: Integral Factor (ソードアート・オンライン インテグラル・ファクター) is an Android and iOS freemium game, announced during Tokyo Game Show 2017 on September 23, 2017. It was released in Japan on November 30, 2017 and globally on March 27, 2018. The game takes place in Sword Art Online, where players can use their own avatar to clear the game, alongside a partner named Koharu (コハル). The game allows players to create their own story of clearing Aincrad from the start of the SAO Incident in 2022.

Game Structure
Integral Factor features a standalone and original timeline for the Sword Art Online series, set in Aincrad, the world's first FullDive VRMMORPG. The story takes inspiration from the Progressive series, as well as the rest of the Aincrad Arc and its events primarily focus on the game's protagonist and their adventure throughout the floors of Aincrad.

The game features three separate narrative aspects: the main story which is a single chronological questline, the "character quests" which take place after a given floor clear without a definitive chronological placement acting as side stories, and event stories which are non-canon narratives tied to limited time events and are never referenced by the former canon stories of the game.

Prologue/Beta Test
On the final day of the Sword Art Online Beta Test, the Protagonist was progressing through a Labyrinth Tower, when he stumbled upon a female player named Koharu. Finding the Labyrinth area too difficult to handle, the girl was delighted to encounter another player in the dungeon. Persuading the boy to teach her the basics of the game, Koharu spent some time grinding alongside the Protagonist, until an unexpectedly powerful monster abruptly spawned in their area. Another player rescued them with a swift attack and advised them to relocate to an easier place, as much tougher enemies periodically spawned in the Labyrinth. Koharu and the Protagonist thanked him for his help and introduced themselves, and asked for his. The strong player introduced himself as Kirito and promptly continued to explore deeper in the dungeon. Koharu had a chat with the Protagonist, talking about how she wanted to get much stronger when the game fully released, after being impressed by Kirito's power. Agreeing to see each other in the full-release version of the game, the two of them shared their farewells as the announcement for the ending of the beta period rung in their ears.