If you are unfamiliar with Tokyo Ghoul, it pays to keep an eye on its plot as follows:
Tokyo Ghoul is set in an alternate reality where creatures known as ghouls exist. The horrifying monsters survive by consuming human flesh and live amongst humans in secret. The story follows a boy named Ken Kaneki after a date-gone-wrong leaves him a half-ghoul. Struggling to adapt to his new life, Ken tries his best to fit into ghoul society, keep his monstrous status hidden from humans, and reign in the insatiable hunger he has for flesh.