After reading the Magic Book for a while, Isaac decided to first research how to store Magic Power.
If he chose to prey on Demons, he would need an additional step: a purification ritual.
He would first need to purify the all-corroding Evil Energy into Magic Power. Otherwise, if he used too much of it, he risked turning into a Demon.
Many Legendary Mages chose to modify themselves into Demons during their Grand Wizard stage, and it was a powerful path to take. However, the key was that the transformation had to be driven by Isaac's own modifications, not by the Erosion of Evil Energy.
The difference between the two was actually quite significant.
Besides, he had no interest in becoming a Demon at the moment. 'Ugly, so no thanks!'
