The Sword of Narathyia Cycle.
Book One: The Sorcerer of a Thousands Names
Prologue.
Rasparin dived from the bow of the ship and deep beneath the waves of the Dread Sea. No sailor would sail there of their own free will, so he had taken their minds. When he broke the enchantment, they would remain only in body only: not truly alive, not dead, not even undead, for even the undead still had some memories of their old life. They would be just husks. He had no time to regret weaving the spell, though it was an anathema to his very soul. They had been good men, but it had been necessary.
No man could dive as deep as he. The Ring of the Leviathan he wore made breathing unnecessarily. He'd found it, after a decade searching, in the tomb of the last King of Rennoir, Genvoila. The last king had risen from the grave to defend the desecration of his resting place, but even the deathly enchantments he had woven around himself could not withstand the great sorcerer's magic. The ring was another necessity. Even with it, it would take hours underwater to find what he sought.
Eventually, he found the first of the enormous metal pins that held the great chain in place. Each link of the chain was as tall as a man and each had been forged from pure Etherium and enchanted by the wizards of the School of Naburg. Each wizard had studied their whole life just to be able to cast the spell that imbued each section with the magic to hold the Great Evil fast and, in casting the spell, each had given their lives. The School of Naburg had stood empty this past millennium as a result.
He followed the chain, pulling each section out of the mud, where it had laid undisturbed for forty generations. Eventually, he reached the captive held by these chains. The eyes of the Dark Lord burned with fire, even underwater. Modorn, the scourge of the thirteen realms. There had been a time when Rasparin would not say his name, not even think it. Now, he was face to face with his nemesis of the aeons again.
He pulled the Sword of Valbiant from its scabbard. None possessed such strength as Rasparin, at least when the sorcerer required it, and the Guantlets of Mandaresh increased his power still ten-fold. Nevertheless, it took ten swings of the mighty weapon to break the first of the chains, and the Dark Lord was held in place by another nine. Eventually, when his strength was all but exhausted, the last of the rings broke free. Modorn, weakened by a thousand years underwater, didn't not move, though those eyes of fire still held a deep terrible intelligence. Instead Rasparin pulled him free and dragged his body to the surface.
Few would have been able cast a levitation spell from water, especially when carrying someone else, but Rasparin was the greatest sorcerer to ever walk the realms. He barked one word in the Old Tounge and floated back to the bow of the boat.
The Dark Lord seemed to wake from his reverie. As he did so, Rasparin knelt before him. "Great Lord, I pledge my allegiance to you. Let me serve you so together we bring the Thirteen Realms to their knees and usher in the Days of Ragathis, and the return of the Eldrich Gods."