Crossover Anime: How Did I Become Iruma-kun?

I unexpectedly transmigrated into "Welcome to Demon School! Iruma-kun" and became the protagonist.
The chairman is my grandfather, so I can be arrogant as much as I want, so what?!
Humble? Cowardly? Afraid of trouble?
does not exist at all!
From the very beginning and after turning evil, I'll crush any demon you may be!
"Sorry, I'm just that domineering!"
"Magic? Is your purity sufficient?"
"All scheming is useless in the face of absolute power!"
Asmodeus Ellis:
"As expected of Lord Iruma, I will follow you to the death!"