#iruma-kun

Some things we know about Derkila (a character who has been repeatedly, overtly paralleled with Iruma):

his request lead to blue flowers blooming on magma

he founded a new country without warning

he tried to channel a river back to his castle

he stopped a war by taking a hit from every side and allowing no one to be hurt

he wiped out an army overnight

These aren't all of what we know about him, but they're crucial, because we see these happen to Iruma.

Iruma praising Asmodeus' fire leads Azz to developing the fire flower 'Amaryllis' spell that we see during Heartbreaker - the manga even directly references Derkila's fire flower demand during this.

His Scala(?) test is all about founding a new country, with very little warning nor leadup (at least for Iruma).

As for the river (which we learn more about in later manga chapters), I think Poro-chan's river of sound at the end of the Music Festival is a deliberate homage to that. At the very least, I believe it counts as the 'river' for Iruma.

So notable points that we haven't seen are "stop a war by taking every hit" (worrying for Iruma, who both is still learning to not sacrifice himself but is also notable for constant dodging) and "wiped out an army overnight" (he's had a variety of successes but I don't think we've seen the true analogue for this yet).