"I'm starting to wonder if working with you is a good thing..." Philo sighed.
Theoretically, an Outer God can't cause trouble for a Legendary Mage after a deal is done. The entity doesn't know the Mage's specific identity—if it did, they would be devoured whole by the Outer God during the transaction!
But that's just in theory. In reality, an Outer God can use unconventional methods to pinpoint a Legendary Mage's identity!
Take this sacrifice, for example. The Master of Billions of Flesh could use the Itra Royal Family to identify Isaac and his group. It wouldn't be difficult for the Demon God to achieve this; after all, It has not only Cultists who believe in It, but also Secret Mages who borrow Its Magic Power.
That's why, under normal circumstances, when Mad Witches make deals with Outer Gods, they choose to acquire power or Knowledge directly. They rarely use an Outer God's power to interfere with people or things in the Real World.
