The Undercover Chaos: Decoding the Atori and Shiida Infiltration Theory in Welcome to Demon School! Iruma-kun
If you’ve been following the story of Welcome to Demon School! Iruma-kun (also known as Mairimashita! Iruma-kun), you probably noticed a huge tonal shift during the Harvest Festival and Heartbreaker arcs. What started as a chaotic supernatural comedy suddenly turned into something much darker, almost like a political thriller set in the Netherworld.
And honestly? I loved that shift.
At the center of this change are two characters who completely shook up Babyls Academy: Atori and Shiida, members of the dangerous organization known as Six Fingers. Their infiltration as teachers wasn’t just a random villain plot. The more you look at it, the more it feels like a carefully planned operation with multiple goals.
As a longtime anime fan who enjoys picking apart story details, I think their mission reveals a lot about the bigger conflict brewing behind the scenes — especially involving the mysterious demon lord Delkira and the ambitious manipulator Baal.
Let’s break down the most interesting theories and what they might mean for the future of Iruma and Babyls.
Who Are Atori and Shiida, Really?
Before getting into theories, it’s important to look at the two infiltrators themselves. They represent two completely different interpretations of demon nature.
| Character | Personality | Role in the Mission |
|---|---|---|
| Atori | Wild, chaotic, violent | Chaos agent and instigator |
| Shiida | Calm, disciplined, observant | Tactical support and possible observer |
Atori is basically the embodiment of the Return to Origins ideology — the belief that demons should abandon civilization and return to their primal, savage instincts.
He’s unpredictable and thrives on destruction.
Shiida, on the other hand, is almost the opposite. She’s incredibly strong, but she’s also composed and surprisingly empathetic toward students — especially Iruma Suzuki.
That contrast alone is what made the infiltration arc so interesting to watch.
Theory 1: They Were Trying to Confirm Iruma Is Human
One of the biggest fan theories is that the entire operation revolved around Iruma himself.
Let’s be real — Iruma is a walking anomaly in the demon world.
Many fans believe that Baal already suspects Iruma is human. Instead of immediately exposing him, he sent Atori to provoke Iruma into revealing his true nature.
Why would that matter?
In demon lore within the series:
- Human blood has powerful healing properties
- It can boost demonic power
- It’s extremely rare in the Netherworld
If Baal could confirm that Iruma is human, he would gain two advantages.
- Destroy Iruma politically by revealing the truth.
- Use his blood as a weapon or power source.
Atori’s aggressive behavior actually makes sense if his goal was to push Iruma into a corner.
Sometimes chaos is the easiest way to expose secrets.
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Theory 2: Babyls Might Be Hiding Something Important
Another theory I personally find fascinating involves the missing Demon King.
Many fans believe Babyls Academy itself may be hiding something connected to Delkira.
Considering that Babyls is overseen by Sullivan — one of the most powerful demons and a former ally of Delkira — the location itself could hold:
- Ancient relics
- Magical archives
- Hidden chambers
- A key connected to the Demon King prophecy
And let’s not forget Royal One, the legendary classroom once used by the most elite students.
Breaking into Babyls directly would be almost impossible. But infiltrating as teachers?
That’s genius.
From inside the academy they could observe powerful students, study magical defenses, and map out hidden areas of the school.
Atori’s rampage may have been more than just chaos — it could have been a distraction to gather intelligence.
Theory 3: Shiida Might Eventually Betray the Six Fingers
Now this is the theory that has the most emotional weight.
Throughout the infiltration arc, Shiida behaves very differently from Atori. Instead of enjoying destruction, she often shows concern for students.
Her interactions with Iruma feel especially genuine.
Some fans even describe her behavior as almost maternal.
Iruma grew up with terrible human parents, so he never really experienced normal affection from adults. Seeing Shiida show small moments of kindness makes their interactions surprisingly touching.
That’s why many people believe she might become a future ally.
Possible outcomes for Shiida include:
- Defecting to Sullivan’s side
- Becoming a secret protector of Iruma
- Acting as a double or triple agent
If the story ever reaches a full war between Baal’s faction and the demon establishment, Shiida could easily become a key wildcard.
The Bigger Picture: The “Return to Origins” Movement
To understand the infiltration, we need to look at the ideology driving the Six Fingers.
Their philosophy is simple.
Demon society has become too civilized.
They want demons to return to their violent, instinct-driven nature.
This movement isn’t just about chaos. It’s about recruitment.
By attacking Babyls and creating stressful situations, they can identify students who enjoy violence, lose control under pressure, or show dangerous potential.
Those are the demons they want to recruit.
In other words, the infiltration wasn’t just about Iruma.
It was also a talent scouting operation.
How This Changes Iruma’s Story
The events at Babyls mark a turning point for Iruma.
Early in the series, he mostly survives situations through luck, kindness, and absurd circumstances.
But after the infiltration, things feel different.
Iruma starts realizing that the Netherworld is far more dangerous than it appears, powerful factions are watching him, and the Demon King prophecy might be real.
And if Baal’s group truly believes Iruma fits the description of the next Demon King better than anyone else, he instantly becomes their biggest obstacle.
What Could Happen Next?
Looking ahead, several possibilities seem likely.
- Babyls will tighten security.
- The Misfit Class will mature quickly.
- Shiida’s allegiance will become critical.
- Baal will escalate his plans.
Final Thoughts
What makes the Atori and Shiida infiltration arc so great is that it adds layers of political intrigue to a story that originally felt like pure comedy.
Instead of simple villains, we get characters driven by ideology, ambition, and personal conflict.
And honestly, that makes the world of Iruma-kun feel much bigger.
Whether the mission was about Iruma’s humanity, Delkira’s secrets, or recruiting dangerous young demons, one thing is clear.
The Six Fingers are playing a long game.
And Iruma might already be the most important piece on the board.
