That was when the Sprites chose to spark a wizard named Cain. They knew that if they allowed some of their magic to be sent into the natural world, they could perhaps find a way to undo the abyss. And indeed, Cain developed the ability to draw out the essence of creatures from the abyss, using his connection to the natural world as a way to create a sort of prison break. Their essence would still be bound to the abyss, though. That is why when a creature sparked with dead magic is killed, it returns to the abyss.
Perhaps if the abyss went away, and the sparks of those creatures were no longer tied to it, destroying them might very well dispel the essence of those creatures, truly killing them rather than simply returning them to the abyss.
Of course, this could prove to be erroneous, and I am not willing to let Malo unleash the power of the Box of Death just to prove a theory that might very well lack validity. Therefore, I must do whatever I can to stop that power from ever being unleashed.
Want to learn more about Balthazar, the Box of Death, or the abyss? Then download Rise of the Dead Magic, Book 1 of the Three Wizards Chronicles.