From Bliss:

In the thick fog that drowns out all sounds and smells, Arama and her brother have the bad luck of running into a group of infamous bounty hunters. These men have gathered in order to hunt an outlaw with a bounty of one hundred million gold on his head. But, who is this man? And can he really be hunted so easily?

The story takes place in the city of demons, Shinjuku, and follows the life of Mephisto, the most powerful demon physician.

The series that spawned the Vampire Hunter D anime.
12,090 A.D. It is a dark time for the world. Humanity is just crawling out from under three hundred years of domination by the race of vampires known as the Nobility. The war against the vampires has taken its toll; cities lie in ruin, the countryside is fragmented into small villages and fiefdoms that still struggle against nightly raids by the fallen vampires--and the remnants of their genetically manufactured demons and werewolves.

God's come down to earth and all hell is breaking loose! Enter a world where demons seen only in dreams are real, oceans swallow cities, and the powers of the mind are preferable to guns.