Oh wow, the brute younger bro actually listens to strategy against stronger opponent.
And I really liked the whole "well, the factories outside got destroyed but we can't do anything about it. Let's just wait for the new business to open up and then help the newbies". Usually the hero would go like "I will protect both sides" but here the MC accepts things as they are.
And poor Barirosa, she just can't stop luring in that Demon Lord. But I liked it how she immediately realised that she fucked up their date and how she and Fulio turned it around to a "thank you" lunch. Fenris and Fulio going full proud parents mode in that last panel of pg14 was cute as fuck.
Now for the problem of miasma - I wonder if lesser demons can equip some sort of miasma restricting gear? Because if they can't stop the leak by their power or equipment then the only other choice would be some sort of segregation. But even that would be kinda fair, since they wouldn't be able to visit (demi)human side and (demi)humans won't be able to visit demon territory thanks to the miasma.
Unless Fulio uses god powers to fix it all up.