Although the anime series Welcome to demon school, Iruma-kun!, has not yet been completed, we can speculate that there is a huge possibility that Iruma will become the next Demon King of the Netherworld.
As fans of the anime series, we’ve noticed various hints and clues scattered throughout the show that suggests a possible future for the protagonist, Iruma. One such instance occurred during the very first episode when the narrator posed the question of who would become the next Demon King, then shows a certain figure sitting majestically in a chair with arms crossed and a glowing golden ring. Circulating rumors say that it was Iruma shown in his evil cycle and that it was a foreshadowing of what is yet to happen in his life.
Following the mysterious disappearance of the former Demon King hundreds of years ago, the demon world was left with a power vacuum within its governing body. Sullivan, despite being one of the most powerful and influential demons in the society and a possible candidate for the position of the new Demon King, chose to accomplish another agenda by coming to the human world and bringing a mortal boy instead. The mortal was Iruma Suzuki, a poor 14-year-old boy who, according to Sullivan, was sold to him by his parents. He was soon adopted and became the grandson of the demon.

A Scroll That Predicts the Next Demon King
In the 5th episode of Welcome to demon school, Iruma-kun! Right after Iruma raised his right hand with a golden ring on his middle finger, Sabnock recalled his conversation with his father about the demon king’s prophecy scroll, which tells a premonition of who will be the next demon king. There he reads the scroll:
All species, far and wide, will fall under his subordination and forging blood packs; he will bestow healing upon all creation, alighting from a far-off land, and carry on his right hand the “Ring of Solomon” that shines gold.
Tracing back to what happened in the anime story, the abnormal Class conducted a race to a flag at the end of the valley to determine their rank as a demon. Skip forward: after all the students had finally made it to the finish line, Kalego immediately explained the procedure of how the Class could find out what their rank was. By putting a hand inside the pocket on the chest of the ranking owl, a small badge containing their rank will be given to them. And so, one by one, the students proceeded to determine what their demon rank was.
However, when it was finally Iruma’s turn to get his own badge, the ranking owl flew away right after he put one of his hands in its pocket. Kalego, who is just saying that the ranking owl is known to be fair and hasn’t hooted in centuries, was shocked when the bird hooted because of Iruma.


Consequently, Iruma didn’t even have the chance to get his own badge as the bird flew away, but shortly after, Clara noticed Iruma wearing a mysterious golden ring in his right hand. Upon the last criteria that Sabnock’s father has mentioned, ‘alighting from a far-off land, and carry on his right hand, the “Ring of Solomon” that shines gold.’ which Iruma fulfilled in this event.
In the 4th episode of Welcome to demon school, Iruma-kun! Iruma fulfilled another criterion written in the demon king’s prophecy scroll. As we can all remember, the abnormal Class conducted a race to determine what their rank was. Right after finishing the explanation of the rules and other reminders, Kalego officially started the race, commanding all the students to quickly leave the starting point by flying off the cliff.
However, Iruma, a human who doesn’t possess wings, is left behind at the top of the cliff because he’s still thinking of a way for him to reach the end. As a result, Kelago thought he was slacking and was thrown off the cliff, where he fell and ended up being taken by a demon crow. While being carried, suddenly, a loud screech echoed through the valley, causing Iruma to yet again fall from the sky. Luckily, he was left unharmed because he landed in the nest of a magical beast, which was the one who let out the blaring noise earlier.

Upon seeing the massive magical beast, Iruma felt doomed, as he thought that he would be eaten. But after staring at the beast, he noticed that it was just in pain because of the wound on its left foot, so Iruma being Iruma, tries to put a bandage on the crow’s wound to lessen the pain, but then Iruma’s blood accidentally fell on the wound of the magical beast, it miraculously provided a full recovery, as if the wound did not exist.
Not only did he manage to help the beast, but he also successfully tamed it and even rode it to move along the course. Going back to what Sabnock’s father has mentioned, “he shall forge a blood pact and bestow healing upon all creation,” another thing Iruma accomplished in this event.
Read more: 13 Interesting Facts About Welcome to Demon School, Iruma-Kun You Probably Didn’t Know

Iruma Sitting on the Demon King’s Throne
In episode 8 of season 2, during Iruma’s evil cycle, he managed to complete difficult tasks and earned the opportunity to use the Royal One’s classroom. The royal one is explained as a highly esteemed classroom built solely for the former demon king, Derkila.
After Kalego uncovered the seal on the valuable school relic, the students gathered around the opulent classroom, only to discover a throne. The Class froze when they saw Iruma walking towards the big chair; Iruma then sat on it with pure confidence, to which Asmadeus narrates, “At that moment, no one was able to move. That form, it’s as if… As if… As if…” – Amadeus wasn’t able to finish his sentence, but it is reasonable to assume that he was saying: ‘It’s as if he was or will be the next demon king.’

The Demon King Explained
In season 2, episode 21 of Welcome to demon school, Iruma-kun! after shopping at different stores in Magical Street, Iruma and Sullivan were seen resting in one of the chairs on the street. While they were waiting for the carriage, Iruma suddenly asked Sullivan about how one becomes a Demon King. Upon hearing those words, Sullivan all of a sudden remembered his memories together with the former Demon King, Derkila, whom he had loyally served.
As Iruma was calling him grandpa repeatedly, Sullivan seemed to space out a bit but suddenly snapped back to his consciousness and became joyful, expressing his happiness about Iruma’s desire to become the demon king. Iruma clarified Sullivan’s misunderstanding by explaining that he did not actually want to be the demon king. He was merely curious about why Sullivan didn’t take the responsibility to become the demon king and how one even becomes a demon king in the first place.
Sullivan provided an explanation that the underworld’s leading demons are known as “the thirteen crowns,” and they all hold important duties. Currently, the thirteen crowns carry the burden of maintaining peace in the underworld. To become the demon king, one needs to be approved by all of the thirteen crowns.

Sullivan emphasized that being the demon king is a significant responsibility since it involves controlling all thirteen crowns. Iruma responds with, “so it’s the demon king’s duty to control almost everything, right?” to which Sullivan answers, “not almost everything. It is everything. Because the demon king is the underworld itself.” This revelation left Iruma in a state of shock.
Sullivan further explains that if all the demons in the underworld were to debate which direction to take, right or left, and the demon king commanded them to go straight, they would create a new path from nothingness and proceed to go straight. He continues saying, “And that’s how rivers in the sky, the magma, the flower gardens, all were created here in the underworld. The demon king is the world. Supreme and absolute.”
Sullivan also mentions his curiosity about the kind of underworld Iruma would create, with a contemplative expression on his face. Iruma became lost in thought, pondering Sullivan’s words. “If I were the demon king….” he thinks. He was so absorbed in his thoughts that he only snapped out of it when Sullivan called his attention.

The Demon King, Delkira Is Iruma’s Father Theory
There is a fan theory circulating on the internet regarding the relationship between Sullivan, Delkira, and Iruma. According to the theory:
- The theory suggests that the reason the Demon King vanished was that he fell in love with a woman in the human world. In theory, they suspect that the Demon King and the unknown human had a child, who was Iruma, making him half-human and half-demon.
- The theory also proposes that some danger or accident occurred in the human world, prompting the couple to entrust their child’s care to another family to protect him.
- Sullivan, upon learning what happened to Delkira during his disappearance, personally went to the human world to retrieve his grandson.

Upon careful consideration, the various pieces of evidence that support the fan theory regarding the relationship between Sullivan, Delkira, and Iruma appear to fit together in a plausible manner. This possibility could explain why Iruma has been treated differently by his supposed parents in the human world, as he may not be their biological child in the first place.
While this theory has yet to be confirmed or denied, the mere fact that it exists adds an intriguing layer to the already complex dynamics between the characters. It raises questions about the true nature of Iruma’s origins and his destiny as a potential demon king.
Read more: Why Did Sullivan Adopt Iruma in Welcome to Demon School, Iruma-Kun?