They have been maintaining the balance of Yin and Yang since ancient times. Whenever the world is in chaos, there are many cases where evil spirits come to do harm to humans. The gods select talented humans and they are given their own guardian god for them to calm the over flow of Yin. This has continued all the way up to the present, so those that are chosen by god are hunters that eradicate ghosts, they are called Ghost Hunters.
From Dazzling Scans: The country of Japan is being terrorized by the undead, known as Revenants. Tachibana Kaguya makes it her life goal to protect her fellow citizens from these zombie-like creatures, just as her father did before her. When she enrols in Reimeikan Academy, a school that specializes in training soldiers that will eventually become part of a movement to expel the Revenants once and for all, she is reunited with Tokugawa Ichii... a boy her father had died to protect—a boy who had promised to build her a world free of monsters.
Shi Shan and his younger sister were about to be sacrificed to a demon plaguing their town, but their fate changed dramatically when a skilled martial artist who was an expert in exorcising supernatural beings came to their rescue. They were taken under the martial artist's wing and trained in cultivation, as well as the intricacies of the otherworldly demons that posed a threat to their world.
From MangaHelpers: Tokitou Haruto, during his first year in middle school, lost all of his friends because of a Science Fiction novel he had read. He was so engrossed in the novel that he started calling men “Kei” and the ladies “Florlain,” which had spread throughout the school at that time. Unable to cope with the sudden exclusion, Haruto continued to isolate himself throughout his middle school years. Now, as a first year high schooler, Haruto faces a new “problem.” One casual day at school, the classroom becomes perfectly still. Time has stopped again. Having experienced this time-stop multiple times, Haruto begins to wonder if this time-stop is actually a dream. But all of this doubt stops when he meets Sakazaki Kuon, someone else who knows and experiences the time-stop. She is also part of a team of members who defends the world from monsters who attack the world using this time-stop dimension: Kohakjal. What relation does Haruto have with a group who fends off time-stop monsters? Could it be that he's the only who can truly fight them off? [Midori-Mori]
In an future apocalyptic world the church once again has regained power, but not to do good, but to serve evil. Cloned priests, called "dragon fly" of the kirihito church use their power, however a shinigami has appeared to stop them and reclaim her past...
From ANN: There was once an ogre (oni) mother who gave birth to a human-looking child. Instead of an ogre's horn, this child was born with a sword in hand called the "Onigirimaru" or Ogre Slayer. He has no name and is only refered to by the name of his sword. Though he appears human, he is pure ogre. Believing that he will become human once all of his kind vanished from the world of humans, he sets out on his destiny to slay all of his kind. Even now, in the mother world of Japan, he is still out there slaying ogres.
The country dog, Woli, becomes a human overnight. She’s meeting again with her old master named Yunjin, at the school that she went to for adaptation to human society. Now that this opportunity has come, let’s be human friends with the Master… It’s not a shame! Woli just can’t stand it since she wants to be patted on the head by her master’s hand and lick his hands too! Can Woli develop a good relationship with Yunjin?
There is a rumor going around about a person called the "Contract Killer." If you want someone killed, the Contract Killer will kill that person for free - if you know how to contact the Contract Killer. Nashi is a girl that's immortal. She wants to die but is unable to. The only thing she loves in this world is a girl named Minamo, who she lives with. Minamo may look like a girl in her late teens, but she's really only 9 years old. Not only that, Minamo has a limited life span, and Nashi doesn't want to lose her. So in order to extend Minamo's life, she secretly kills people that someone else wants dead, for free. As a reward, she recieves "time" from the Time Merchant, which she then gives to Minamo to extend her life.
Rara, a girl from the demon world, arrive on earth with only one goal in mind: To do as many bad things as possible. Sound easy, doesn’t it? It doesn’t sound as easy as it seems when Rara starts to develop the feeling for a certain someone that she shouldn’t have. “Rara, don’t forget not let the human aware that you’re a demon.”