I will just say it again.
This is just about one of the most grabbing, epic stories I have
ever read in short, god-dammn life.
Yes, it's that Holy, Freaking,Blazing Magnificent.
...Well, as long as you're following the Haru route.
Calling it a "mere story" is just a plain offense.
That was probably as bittersweet ending as you can get. Still, I love how Kyousuke finally did a massive "Fuck you" through his live into Maou's face, and was finally able to reunite with Haru and his kid and go on to live as a family.
Also, my money's on Kiyomi, Kouysuke's late sister name.
It would be kinda fitting, wouldn't it?