The recent discovery was fascinating, especially considering the current world-wide circumstances! When one pictured a demonic apocalypse, they thought of death, destruction and plagues; Most of those things were already happening, but that was not the point.
The point was, that within all of that mess, no one expected a bright side or a godly advantage of some sort. People definitely didn't expect to be healed all of a sudden, and get a fraction of their powers back, after weeks of feeling sick and close to death! It was unexpected, and was perhaps the best thing that could happen in an apocalypse!
When Bardeelus saw the numerous fireballs pop up in front of him, he got exceptionally happy, the happiest of them all. The 'fire mages' had powers once more, and it wasn't a secret regarding how they got their powers back, he immediately pieced the puzzle together.
"It's the demon meat, no doubt." He thought, and for this part he felt specifically involved.