Instead of summoning a beast, Iruma accidentally summons Kalego himself as his familiar.
If you are looking for fan-created variations or "X Reader" stories based on this specific chapter, you can find them on creative platforms like DeviantArt or Wattpad . If you'd like to dive deeper, I can look into: and limitations Other students' familiars (like Clara’s or Asmodeus’s) Summary of Chapter 3 and the next major plot points Summer Rain 18 by Kashiaka on DeviantArt
While Iruma is actually terrified, the rest of the school views this as a "Power Move." Summoning a high-ranking demon teacher as a servant makes Iruma look like an incredibly powerful and arrogant prodigy.