i hope the artists doesn't shot herself in the foot with that. i'm personally not interested in those side characters at all, i don't care about them, i'm not interested in what happened or will happen with them etc., especially the killer boy lol.
she said in the extra that the second couple was quite popular, but i honestly think that was only for the psycho vibe and the bara uke. now both is gone, and unless she revives the police officer (which i think most wouldn't want, i wouldn't) or have them suffer in hell, that couple is history.
while the purple haired demon could maybe be interesting per se over time, not in combination with the killer boy. (why exactly are they edging him on to kill anyway? as a food source? they didn't care about the serial killer before?)
so unless the side story connects with our dear beloved demon and vampire, i am out. and i don't think i'm the only one who was here for those two.

wait wait, I thought this manga ended can someone explain