And so it ends. It's hard to say whether the manga was axed, or the author just gave us another of their teases with that last page.
Nevertheless, I believe that the manga ended on time - having resolved all character arcs and personal growth, but before Yuko's shtick of converting everyone got too stale.
And it did give us it's lesson - we make our own enemies and sometimes it takes incredible denseness and overwhelming power to ignore our survival instincts and see everyone for the generally nice people/demons that they are... Yeah, kinda unfair.