Yami ni Naku Oni

Kyou is the last of the Puppet Masters, those with the power to defeat the Dark Demons that feed on negative emotions. He travels with his two guardian Light Spirits to rid the world of the Dark Demons, knowing that only then will time resume for him. Yet overshadowing every victory lies the truth behind the slaughter of his clan and the fate of his best friend...

(Source: Storm in Heaven)