Under Fallen Stars

Under Fallen Stars is the second book in the Threat from the Sea trilogy by Mel Odom.

"The sea war rages up and down the Sword Coast, leaving the busy harbor of Baldur's Gate in flames. Following his mad quest, the evil Iakhovas has found a gateway into the protected waters of the Sea of Fallen Stars, and now no coast is safe from his marauding armies of the deep."