I agree. The misfits class is definitely made intentionally. I'm very excitedd!
No, Baal wants Iruma's blood because he confirmed he's covered by Delkira's mana (I just reread fr Deviculum up to now). He wants to use his blood to strengthen him not necessarily to return to origins, since Delkira is the strongest demon on record.
Narnia is 13th crown and is part of Baal's crowd although his motivation is very Nazi-like (i.e., netherworld is for demons only - all other creatures are trash and should either serve demons or be their food or just die). Baal is now the demon king so they have to tread carefully as he is backed by the deity princess. But I think some will help on the sly.
I'm just happy they have other powerful allies like the asmodeus and barbato clan. Mephisto as well. That's 3 members of the 13 crowns, plus the 3 greats, plus their classmates and their families (all who seemed at one point in time or another been in the position of being a member of the 13 crowns or a high rank, I'm also guessing they were all deliberately placed in the same class as Iruma by grandpa for the sake of them becoming his support in the future) , the azazels, the school faculty. With enough convincing they might be able to rally the rest of the 13 crowns since it looked like only baal was the bitch..oh and Kalego's brother.
I think the enemy's goal is to use iruma's blood to have demons return to their origin - is that the term they used I forgot. Anyway I'm assuming that's what they want and that's the kind of netherworld this wanna-be demon king wants.