Zero: Black Blood

Rei Suzumura, Zero the Silver Fanged Knight, is patrolling on his own when he encounters the white Horror Ring, who has created a commune where Horrors and humans live together in harmony, so long as one human a month allows themselves to be devoured by the Horrors. Rei, along with Makai Priest Cain and the knight-in-training Yuna are ordered by the Makai Senate to slay Ring and free the humans under his thrall by means of Yuna's mother the Makai Priestess Iyu.

Synopsis

Rei Suzumura, Zero the Silver Fanged Knight, is patrolling on his own when he encounters the white Horror Ring, who has created a commune where Horrors and humans live together in harmony, so long as one human a month allows themselves to be devoured by the Horrors. Rei, along with Makai Priest Cain and the knight-in-training Yuna are ordered by the Makai Senate to slay Ring and free the humans under his thrall by means of Yuna's mother the Makai Priestess Iyu.