This shit is dark Dark. And I mean like "tenderly-fucking-a-demon's-innards-while-they're-still-alive-and-then-becoming-the-object-of-the-demons-affections-therefore-being-turned-into-a-demon-and-then-plotting-to-kill-their-master-by-striving-to-surpass-all-other-demons" kinda dark. I'd suggest to discard your morals for this one. But hey the art is *chef's kiss*
You may feel your favorite manga should be gathered together into distinct categories for your own reference and, now, you can do this with a LIST. After you've created your list or lists, you can proudly recommend them to other manga fans to showcase and share your taste in manga.
MADK