WARNING: The following contains minor spoilers for Welcome to Demon School! Iruma-Kun Season 2, now streaming on Crunchyroll.
Welcome to Demon School! Iruma-Kun is a popular isekai fantasy anime starring Iruma Suzuki, a 14-year-old boy whose own parents sold him to a demon named Lord Sullivan and was soon enrolled at the magical Babyls School for young demons. Iruma's world has completely changed, but his heart has not.
Most works of fiction feature a dynamic lead character, someone who changes not only in their skills and knowledge but also the content of their character. The opposite is a static character, or someone who does not undergo significant change during the story. Once in a while, though, this static character is exactly what the story needs -- enter Welcome to Demon School!'s Iruma Suzuki.
The Role & Appeal Of A Static Character Like Iruma
Iruma Suzuki has appeared in two solid seasons of Welcome to Demon School! Iruma-Kun, and during that time, his character has undergone very limited changes that focus on his magical power levels and abilities rather than the content of his character. That is to be expected for most shonen leads -- even reluctant ones like Iruma, who subverts the OP power fantasy trope for the most part. Iruma's worldview, personality and general interests remain the same, and he has shown little growth on the inside. That's because he sets a good example for the other characters.
Iruma begins the series as a good-hearted, compassionate, kind, optimistic and loyal person, and he has little room to grow in that regard. Rather, Iruma draws out the best in the people around him, challenging them to change on the inside instead. The protagonist is a positive influence who cultivates the people around him, and that's the source of Welcome to Demon School!'s compelling character arcs.
Viewers aren't waiting for Iruma to change as a person -- instead, they watch Azazel Ameri become better-rounded and deeper, such as on her first date with Iruma, and Asmodeus Alice undergoes meaningful changes around Iruma too. Every story needs dynamic characters who go through a compelling character arc. If the protagonist won't do it, then the side characters will instead, and that is the heart of Iruma-Kun. Iruma can be used as a measuring stick for how far the other characters have come.
Iruma Suzuki, The Prophecized Demon King?
A story such as Welcome to Demon School! can have a static character as long as he or she has a well-rounded and likable personality, and Iruma fits the bill. Aside from gaining enough magical power to become a hero in Walter Park and beyond, Iruma is largely the same. He's an anchor for this colorful isekai adventure, where demons can change as people and Iruma explores new vistas, giving the viewers some stable ground to stand on. He is also static for another reason -- he might just fulfill a prophecy about the next demon king.
The prophecy states that a person from another world, bearing Solomon's ring, will arrive and become the next king of the Netherworld, and Iruma fits that description. What is more, the previous demon king was a laid-back and kind person who created a peaceful demon world, and Iruma likes his world just as it is. In the king's place, Iruma would surely have created a similar Netherworld, suggesting he really will become the next king so the realm can remain stable. The old king is simply passing the torch, and if Iruma doesn't change, then he will still fit the prophecy if -- or when -- he's ready to assume leadership.
Iruma does have an assertive and punkish evil side, but aside from that, he aligns so closely with the prophecy that there might be trouble if he changes too much and no longer matches all the clues and hints from the prophecy. For that reason, Iruma must remain the same; the people and world around him must change and adapt as Welcome to Demon School! continues.