A Psychic (超能力者, Chō Nōryokusha) refers to a human who was born with a mutation, an Abnormal Ability (異能, Inō) gained as a result of the brain being able to comprehend a 'channel' ("common sense", or perception of reality) not native to regular humans.
The term psychic is to define a human who possesses super natural powers and has the ability to use Spirit Energy (or Demon Energy in some cases) amongst other things. Psychic Power (超能力, Chō Nōryoku), also referred to as Extrasensory Perception, this is a catch-all term to refer to the flow of supernatural energy that cause supernatural phenomena to occur; it's a form of nature interference that to the psychic comes as naturally as breathing. Psychic powers are the ultimate ability of humans, who have become an existence independent of nature. However, these powers are generally incomparable to the great abilities possessed by other races. In the end, they are only human.
The psychics who gained their abilities through the door to the demon world can only use their abilities within an area known as their territory, which is often a radius of varying length around the psychic. However, this territory is mostly a regression. Modern societies are so complex and contain so much information that normal humans would disregard anything not necessary for them. Those who can access their territory, on the other hand, will irrevocably record everything in their memories - an information overload.