Is this small passage worded in the correct way?

Once they traveled through the Pass of the Soulreaver, Quenthel’s group came upon the Planes of Soulfire and encountered an elite force of yugoloths commanded by Inthracis. While Quenthel summoned a mighty demon to assist in the fight against the yugoloths, Danifae called upon Lolth to send millions of spiders to their aid. Pharaun immediately engaged Inthracis himself, and following a vicious magical duel, he defeated the ultroloth mage, but was left magically paralyzed.