Light Novel / DDD
Pictured: Karyou Kaie

DDD. Decoration Disorder Disconnection. A set of novels by Kinoko Nasu that explores the notion of "Demonic Possession". No direct connections to the rest of the Nasuverse yet.

In a certain part of Japan, there is a syndrome known as Abnormal Agonist Syndrome. People argue just what this is, but it's the next level beyond "mental illness" and some people even argue that it's Demonic Possession. Some argue it's just a mutation triggered by emotional levels not natural in normally functioning human beings. It's called "Agonist Syndrome;" where the mind shapes the body. And since the mind usually isn't healthy... All of these take place in Shikura City.

To combat this outbreak, the city government has made the Origa Memorial Institute the main hospital for anyone affected by AAS.

Also, the real demons are a little bit upset by these people stealing their thunder. Well, technically, demons aren't real. Neither are what most Agonists turn into. It takes something unreal to fight something unreal. Confused yet? Yeah, this series will do that.

Arika is a rare Abnormal Agonist Albino with one arm who is considered rather harmless. Slightly odd, he'll comment that one should never tell him anything serious during daylight hours, and nothing silly at night. He is employed by rather bizarre and sadistic yet beautiful man-boy named Kirie Karyou, who claims to be a "Demon Master." His only job is to put on and take off Kirie's prosthetic limbs, something for which he is paid 200,000 yen ($1600) a month.

Two volumes are compiled and there is a side story called "3/16 Incident: Outside the Universe". There is suppose to be a third volume, but there's no word on when it will come out.

Here's an online translation.

DDD provide examples of: