The skeletons had varied weapons. Some used swords while others used spears or even bows. That made the fight much harder for William. While fighting in close range with the skeletons, he had to keep his attention on the ones with bows.
A hit by an arrow would hurt a lot. It wasn't a good thing to get hurt during the first hours of the exam, as it would lower his chances of passing the first part.
However, even with the numerical advantage, the skeletons were still too weak compared to William. All of his sword slashes had tremendous force behind them, and the skeletons couldn't withstand it.
One even tried to block with its shield, but it was destroyed instantly, and the skeleton met the same fate. As for the arrows coming his way, William's reflexes were so great that he dodged or deflected them using his sword.
