Sword Art Online, (Light Novel) Vol. 17

The final stress test bleeds into its second day. Driven to desperation by the Integrity Knights^ coordinated assault, the Dark Army reveals the ace up their sleeve! Critter, who has been observing the battle from the Ocean Turtle, has successfully created a gateway into the Underworld and masked it as an invitation to "an open beta test for a new, unannounced VRMMO." This digital invite bolsters the ranks of the Dark Army by the tens of thousands! Having already been pushed to her limits, the thought of taking on a fresh wave of bloodthirsty enemies fills Asuna with dread. But just when it seems like all is lost, two new deities of the Underworld appear to take up the fight: the Sun Goddess, Solus, and Terraria, the Earth Goddess. And the ones in possession of these super-accounts are none other than Sinon and Leafa!