Legion has only seen this kind of fundamental change twice. That was when the realm lord froze the plane when he met Legion-7 for a deal. The first time was when Zernon of the Zargoth plane froze his plane. Zernon was still lacking because he only froze space but that is still powerful.
Zernon's ability to do so shows that cosmic force can be wielded with the law of order. But they haven't gone through Zernon's route. They have gone beyond it to achieve something extraordinary.
Time and space of the void universe can be manipulated beyond what is allowed and Will can be made manifest in any manner. Anyone who has ever experienced it would be changed too. If it is a forbidden fruit then it is too late for them to rid themselves of it because they are already addicted.