Charon, in Greek mythology, the son of Erebus and Nyx (Night), whose duty it was to ferry over the Rivers Styx and Acheron those souls of the deceased who had received the rites of burial.

Why does Charon rage at Dante's presence?

‘ (3:91-93, Mandelbaum trans.) Charon’s reaction–believing that Dante is there by mistake–is natural: not only is the Underworld reserved for the dead but there is also very little precedent for a living being to journey to Hades and return to the upper world.

How does Charon mock the souls?

Charon mocks the souls, and enjoys telling them that there is no more hope for anyone here and they all will suffer forever without any chance of being saved from the tortures. When Dante and Virgil come to him, Charon is angered by the sight of the living man and grumpily refuses to take them aboard.