Board Thread:Questions and Answers/@comment-116.86.100.93-20171204092241/@comment-34962159-20180719020928

Aureolus and Ars Magna were introduced long before actual Magic Gods appeared in the series. We've never seen Ars Magna used against Magic Gods, but from we've seen of the latter's capabilities, it probably wouldn't be enough to defeat them. Remember that Stiyl, at this point, had never encountered Ars Magna or Magic Gods in person.

To be more exact, the Blasting Rod makes Aleister's magic ten times more powerful than what the target thinks it is. So if the person thought Aleister is weaker than he actually is, he would still be ten times more powerful than that expectation. To truly weaken Aleister, it would be necessary to think he is less than one-tenth his actual power.

No, Aureolus no longer has Ars Magna since he doesn't have the 2000 students that he used for the required chanting.