Is It Wrong to Try to Pick Up Girls in a Dungeon? On the Side: Sword Oratoria, Vol. 4 (light novel)

After the tumultuous events in the Dungeon, Aiz has finally reached the vaulted Level 6! But in spite of this amazing news, the Sword Princess seems to be completely depressed. Meanwhile, from the depths of the Dungeon comes a mysterious crystal ball that's about to plunge both underground and surface worlds quietly into chaos.