Sword Art Online Progressive Scherzo of Deep Night, Vol. 3 (manga)

The fifth-floor boss, Fuscus the Vacant Colossus, brings the raid party to the brink of destruction when it reveals mechanics that are completely different from the game’s beta. On top of that, PoH, the leader of Laughing Coffin, attacks Kirito to obtain the Flag of Valor. Will Kirito be able to overcome these unexpected trials and make it out of the fifth floor alive?!