Demons may be beings of magic, but ultimately they aren't that fundamentally different from humans, at least not by nature. In a way, Iruma isn't there to force them to do anything, but he is the "permission" to go against the norms of Demon society.
This story is very much an examination of nature versus nurture. At this point, Asmodeus must know he's technically stronger than Iruma, so his dedication must stem from something more. Sabnock may actually be one of the first characters to show "casual" empathy as well, noticing immediately and asking Iruma "what's wrong?". He's also completely unsurprised at Iruma wanting to help and doesn't hesitate to follow.
The Demons are teaching Iruma to be stronger emotionally, and in turn he is teaching them that empathy and friendship are not weakness. It's also refreshing that this far into the story, Iruma has gained the respect of his classmates by his actions, not by demonstrating physical might.
I notice a lot of people comparing him to Deku, but I don't think that's appropriate. His ability up dodge almost anything has been his own ability since the very first chapter. Iruma is becoming more brave, but his ability to dodge isn't magical. He's a better leader than Deku despite not even trying, and has much healthier relationships with his classmates. MHA has lots of great points – I have enjoyed it immensely. Still, Deku's character development and relationships are heavily tied to him learning to better use his power and improving his physical ability. Iruma's development is driven by his friends, even though he's no physically stronger now than before.
Note: One endless frustration I have with MHA is the absurd one-sidedness between Deku and Bakugo. Those two should have developed a cold distance long ago. Sabnock may see Iruma as a rival, and Iruma mostly sees him as a friend, but they generally treat each other well and the geniality clearly goes both ways. It's good that as a reader, I don't feel like the only reason they still talk to one another is plot armor.