The thing that blows me away about all of this is that evil phase Iruma doesn’t have any MORE information than normal Iruma. He’s not suddenly aware of things he shouldn’t be.
I think this means that Iruma has absolutely been paying attention to everything in his classroom with perfect detail from the start.
He knows every power his classmates have by heart and understands how to use them, he knows about the lore and history of the school.
The ONLY thing he’s lacking is the drive to use it to his own advantages.