The dual theraponte here at I.08.113 is referring to Sthenelos and Eurymedon, named at I.08.114, who as we know from related contexts are respectively the chariot drivers of Diomedes and Nestor. For the moment, however, Nestor has replaced Sthenelos as the chariot driver of Diomedes. And, also for the moment, Nestor has also displaced Eurymedon in the role of chariot driver. For now, then, both Sthenelos and Eurymedon function merely as attendants.