Sword Art Online Ordinal Scale, Vol. 4 (manga)

This might be a game, but it’s not something you play.Kirito is still trying to figure out how to recover Asuna’s missing memories. When all hope seems lost, the enigmatic girl who exists solely in Ordinal Scale appears before him and explains the only way to uncover the truth is to rise to the top of the OS ranks. But will he make it in time? And even if he does, will he be able to defeat Eiji…?