They ought to have been the mere cruel words of a goading enemy. They ought to have been received in one ear, and then dismissed in the head a mere heartbeat later. But the strength of that shout, it brought them to shiver. It was the shout of a General, after all. If Blackthorn had spoken such a thing, in such a situation, they might have shaken as well. However, they would not have shattered as they did then.
The line that had held to meet Oliver lost their strength. What he was met with was something far weaker. He slowed not against them, but sped up instead, feeding on their fear. Then, the row behind them, seeing how easily the men before them had been dealt with, and having heard Oliver's fearsome command, did indeed start to break. They opened up a gap in the middle, doing anything that they could to get out of his way.