Later, he would claim it was an accident, that he did not intend for it to happen. He would cry his crocodile tears and convince that soft-hearted young fool who had just taken the throne that he was innocent. It would be easy. After all, he had never feared the monsters.
But in the moment, he reveled in the power he could feel coursing through him. The long years of research had finally paid off. It was indeed possible for a monster to absorb a human soul, and the result was every bit as powerful as the myths said.
The thing about most monsters was that they foolishly believed themselves to be more enlightened than humans, claiming that they were made of hope, compassion and love, and were therefore morally superior to their more mundane neighbors. They went around spewing their ridiculous belief that what they called "souls" were truly the culmination of one's being. His extensive research indicated otherwise. A "soul" was a collection of an individual's magic. The ability to manipulate a monster's form or pry into their thoughts through contact with one of the objects was merely due to the fact that a monster's body was composed almost entirely of magic.
He did not intend to correct their misguided beliefs, as they worked to his advantage. After all, if all of monsterkind "knew" that monsters were too noble to commit a premeditated murder for the purpose of stealing a human's soul, they wouldn't even consider the possibility.
No, he had never feared the monsters, and now there was no need to fear the humans either.