Commentary Inf VIII 18

The guardian of the river, who will be identified as Phlegyas in the next verse and who is apparently not in the least interested in Virgil, would seem to believe that Dante is a newly arrived soul cast down to his eternal punishment or that he is a condemned soul who is trying to escape.

As Padoan points out (DDP Padoan.Inf.VIII.18), Dante elsewhere several times uses the adjective fello (here translated as 'damned') so as to associate it with wrath (see [Inf XVII 132]; [Inf XXI 72]; [Par IV 15]).