Theory time~ ...again
Baal will end up being temporary Demon King. His main duty will be still to sort out the Netherworld's problems.
Here's the thing, he is a TEMPORARY king. He isn't acknowledge by the crowns, nor does he hold a Yodh rank. So he cannot be King. However, he still has Shura's support. So everyone is careful in acting and what they say.(aka, unlike how no one can disobey the demon king, they can reject Baal's orders. Though its still hard because of Shura)
At the very first, Baal would almost seem like he was a good king.
But, everyone will realise that there is more and more chaos happening around the Netherworld. The already harsh environment and survival, has increasingly became even more difficult and there has been more and more wars reported.
Anyway at some point, since Iruma has basically been outed as a human, and everyone has already good feelings with him because of his role with the Barbatos, he was give the Demon King role, or not the true role but in training till he is fully qualified. But this is all in secret, away from Baal's and Narnia's eyes.
Oh, btw, Iruma doesnt know this. He was told that, to be able to stay in the Netherworld, he needs to rank up and become stronger. Strong enough that he will be qualified to be part of the crowns. Also, he will be the main face of the Sullivan family, as he has been sentenced to house arrest.
Training arc! Intense training to become a demon, demon etiquette, demon history, and many more that he needs to learn to be able to live comfortably. And also socialise with alot more demons.
....which isn't a problem, as the crowns watches. They have never met a being with as much natural charm as Iruma does(aside from succubuses, but even then its like he exceeds them?! Amuryllis what kind of charm training did you do?!)
They dont have to worry much about gathering allies as well. The Barbatos have already given their support, and the entirety of Babyls, from the staff to its students are in support of Iruma. His familiar being a Rank 8 Naberius demon, who is allies with another power Rank 8, and these 2 are basically the subordinates of the strongest SD Opera.
Additionally, the Many Ears clan, despite their start being rough due to the protests of their independence, have rejected working with any demons that will be against Iruma. With Mephisto and Asmodeus being some of their main protectors, they have nothing to worry about.
Don't forget about his classmates. They're all Rank 4, and acknowledge by their mentors. Adding on to that, their mentors are some of the best and strongest in their fields, with some working directly under some of the crowns themselves(like Mr Hatt and Paimon). These kids have so much potential.
Also, tf you mean this kid crossdresses and is one of the most popular evidol in the Netherworld, despite his small appearances?!
Also, what are these titles? Demon Slayer? Harem King???
.
.
Anyway. TLDR: Baal becomes temp demon king and cause chaos and destruction to netherworld, crowns resist by choosing Iruma to be the next demon king(iru doesnt know this) and trains him to become stronger to be able to rightfully take his place as demon king, crowns start to take note that this kid(iruma) is fking insane??
