The devil did not believe a word of it. As far as it was concerned, Adam plainly meant to lock it up and use it as a test subject, and was lying about "solving its problem" to string it along—as if Adam would ever be that kindhearted. But it had no way to resist at all. Once it realized Adam truly had no intention of letting it go, it could only slump limp and hopeless in the cage, praying to gods that could not possibly exist in the Mage World to come and save it.
After soothing the devil, Adam left the cavern that held the cage and laid the equipment out piece by piece, sorted by category. What he had to do at this stage was digest the knowledge he had plundered, in preparation for the ultimate goal: a virus built on abyssal flesh and blood.