Sword Art Online Progressive 8 (light novel)

The protracted secret feud between the Nachtoy and the Korloy families, who control the casino on the seventh floor, takes an unpredictable turn when Kirito and Asuna intervene. But when Kirito attempts to expose the misdeeds of the Korloy family, he ends up stumbling into a trap. Now he has just two days to unravel a mystery, put an end to an unscrupulous conspiracy, and defeat the floor boss. It's all leading up to a showdown in the arena where everything's on the line!