The anime Welcome to Demon School! Iruma-kun (or Mairimashita! Iruma-kun) tells the story of Iruma, a young man who lived in the human world and performed various dangerous tasks to survive, until he was "adopted" by one of the three strongest demons to become his grandson. Curiously, his life improved significantly from that point on. After the chaotic events of the opening episodes, Iruma enrolls in Babyls, a renowned school for demons where his new "grandfather," Sullivan, serves as the headmaster.
The story is well-structured and features interesting progression, though it is frequently interrupted by "breather" moments where the author shifts to telling random side stories amidst the main plot. The anime's key events usually revolve around challenges that Iruma and his friends from the "Misfit Class" must overcome; notably, subtle hints regarding the series' future or ultimate conclusion are often dropped along the way.
Many of these hints point toward one of the most popular theories surrounding Welcome to Demon School! Iruma-kun: that Iruma is destined to become the "next" Demon King. We will explore this theory by examining specific moments in the story that you might have overlooked.
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Prophecy of the Next Demon King
In the Demon World where Iruma ends up, there is a prophecy that seems to describe him almost perfectly: "He shall make one and all of his servants; He shall form blood pacts and heal all demonkind; He shall descend from a foreign realm; And wear the golden ring of Solomon on his right hand."
Source: Mairimashita Iruma-kun Fandom
The first part—that he will make everyone his servants—can be interpreted as making everyone his friends; in one episode, his friends actually mistake this bond for a soul pact. As for the second part—healing all demons—human blood has the ability to boost demons' powers and heal their wounds, something he demonstrated with the monster in the valley.
Regarding the part about coming from a different world, he literally came from the human world, so that’s another box checked for the prophecy. Finally, the "golden ring of Solomon" refers to the ring Iruma received from the owl, which contains Alikred inside.
Alikred = Derkila?
The next theory supporting his path to becoming the next Demon King involves the "Gold Ring of Solomon" from the prophecy. It came with Alikred—a name that, when read backwards, spells "Derkila." Derkila was the previous Demon King who is "supposedly" lost or missing, with his current whereabouts unknown to anyone.
Every time Iruma ranks up in the Demon World by meeting a specific requirement, Alikred grows stronger. Having Alikred as an ally is essentially having the former Demon King assisting him in becoming the next one; furthermore, there is a theory that they might merge in the future, as Alikred has mentioned at times that he will one day disappear.
Iruma's Resemblance to Derkila
Finally, setting aside the fusion theory, many believe that Iruma might actually be the son of the former Demon King Derkila. This would explain his possession of Derkila's magic and position him well to become the next Demon King.
Source: Mairimashita Iruma-kun Fandom
Neither the anime nor the manga reveals Delkira's face, but his hair color—a dark purple or blue—closely resembles Iruma's. It is also worth noting that when Iruma entered his "Evil Cycle," he bore an even stronger resemblance to Delkira's image; during that time, everyone treated him with a level of respect akin to standing in the presence of the Demon King himself.
