So im guessing its gonna take the route where the demon lord falls for Barirosa and leads to them getting married and ending the war which would also make her familys reputation regain even more glory than it used to have. Or something like that. win-win. Assuming it doesnt go the harem route which it doesnt look like it is.
He basically crushes every romance flag that comes his way because he only wants Risu
About the Demon King:
He's actually already married to Ulminus but she thought he was joking so she gets all flustered when he makes it known he wants to marry Barirosa until he tells her to check her titles and Demon King's wife shows up
I am pretty sure that what Mr. Hero said is going to getb a full 360° turn just him getting yeeted out the forest. And I also think that the demon King is going to get involved in this as well.