Ring (リング Ringu?) is a powerful birdman-like Horror who serves as the antagonist of ZERO: Black Blood, appearing in the form of an European gentleman dressed immaculately and predominantly in white a suit.
Despite being a Horror, Ring finds violence distasteful yet sees humans to be more selfish than Horrors, unable to comprehend why humans have to fight Horrors and not sacrifice one of their own for the greater good. As such, he sees his ideals to be a far better alternative to the existing relationship between Horrors and humans where the former consume a larger number of the latter without restraint. Though Ring usually opts to talk things out instead of fighting, he is nonetheless a powerful fighter. Ring also has feelings for Iyu that border on love and obsession, as her singing maintains his sense of self and keeps his impulses as a Horror in check.
His entire body made of feathers, Ring can use them for various means such as creating weapons, like his sword, and wings. He can also assume his true form, though the downside is that he becomes a mindless beast.
Ten years prior to the events of Black Blood, Ring witnesses Kuroudo and Iyu fighting Horrors and becomes lulled by the latter's singing voice to the point that his Horror nature is subverted. Saving Iyu, Ring learns of her dream for a world without conflict and resolves to make it so by creating a community as the first step for his kind to co-exist with humans. Ring offers his community to those who have no where to go, people who became fugitives or simply escaping from harsh reality, only on the condition of a mandatory lottery once a month involving nutrient supplements. With the addition of a pill containing crystal Horror blood mixed into the supplements, there is a 2% chance that one among the humans would become a Blood Dolce that would be served to the other Horrors within the community to ensure the fiends do not slaughter everyone else. Through Iyu's singing, Ring ensures none of the humans under his protection would not fret over such a detail.
Two years after killing Kuroudo, Ring faces Rei Suzumura as he eventually allows the Makai Knight to find his location to prove his ideals are the right way to go. However, sensing Iyu singing for her daughter Yuna instead of for him, Ring unconsciously assumes his true form. Though he pleads Iyu to sing before he ends up acting his nature of the Horror, Ring ends up eating Iyu when she refuses to honor his wish. From there, Ring battles Zero before Yuna uses her singing voice to calm the Horror long enough to be killed. In his dying words, Ring cursed Rei for continuing the senseless conflict between humans and Horrors.
- Ring is portrayed by Thane Camus (セイン・カミュ Sein Kamyu?).