This was a really vicious move by Sheyan. Taking advantage of the fact that he could use magic to transmit his voice to all ten thousand Corsairs, he quickly seized the high ground, forcing Arathorn into a corner.
If Arathorn chose to come on board the Dingyuan, the ball would be out of his court. Even if Sheyan could not persuade Arathorn, he could just kidnap the corsair captain and sail away. With the Dingyuan's ability, it would be way too easy to delay the leaderless Corsairs of Umbar for a few hours.
