The basis is that the mc doesn't have to be necessarily 'evil', but they wont hesitate to manipulate or murder (even indirectly) others for their gain or for revenge. Doesn't matter if the victims themselves are inherently bad or evil Or are just a pure asshole
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.
Hero Killer