Nothing made sense to Joker as the one he had just made a toy for entertain had resisted the madness that should have overtaken him. Even the soul mutation potion had been a joke when it came to power. Just a temporary usage that would create a more brutal monster. One that Joker could have later used for further servitude.
All that purifying, all that work to have such a potion, and there they were, completely fine! It was outrageous. But as Joker tried to lash out and force an explanation, existence itself put pressure on him.
The rules that governed the greatest and most powerful races were there for a reason. Existence had created them through various means, they had developed and taken certain powers for themselves. As such, came the balance that existence needed. Therefore, the drawbacks of those powers became shackles.