At the news, Dante turns even paler than Virgil, quite an accomplishment, considering Virgil is a ghost.
In a fatherly way, Virgil tries to reassure Dante. But he is so distressed that his words—usually smooth and eloquent—come out choppy and incoherent. Virgil is stuttering.
Dante notices his hero’s broken phrases and this only deepens his fear.
In an indirect way, Dante asks if anyone from Limbo has ever descended this far down in Hell before.
Virgil answers that even though it’s rare, it has happened. In fact, he has traveled down to the deepest level of Hell before, on a mission to recover a soul for the witch Erichtho. (No, this doesn’t mean Virgil is evil, but simply shows that he has an extensive knowledge of Hell and its inhabitants. Besides, the mission wasn’t really evil.)
Dante's gaze has drifted up one of Dis’s towers, to take in a horrible sight: three blood-spattered women hanging pell-mell from the turrets. And they have snakes as hair.
Following his gaze, Virgil reacts with disgust, identifying the terrifying trio as the Furies. He names each one for Dante’s benefit: Megaera, Allecto, and Tisiphone.
The three ladies scratch their chests with their talons and threaten Dante, warning him that Medusa is coming to turn him into stone.
Virgil understands this danger because he reacts by turning Dante away from the Furies, ordering him to close his eyes, and even covering them himself.
Dante hears the wild rush of something approaching. Something big and possibly scary.
Virgil tells him to open his eyes to witness Heaven’s messenger.
Dante sees a figure coming with the force of a hurricane, scattering thousands of souls before it, yet its only movement is to thrust the air out of its way with its hand.
When this Heavenly Messenger reaches Dis’s gates, he has only to wave his wand to open it.
Then he speaks, admonishing the inhabitants of Dis for resisting God’s irresistible will.
Dante, awestruck, describes his words as "holy."
After the wonder has worn off, Dante and Virgil enter the city to see more pain and suffering.
This time, the ground is pockmarked by open tombs, out of which flames burn. There are sinners inside those burning graves, screaming in agony.
Here in the sixth circle, Virgil explains that the arch-heretics are punished. Reading Dante's thoughts, Virgil tells him that there are many more suffering here than he might think.