DDD

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. 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...

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.

Here's an online translation of the first chapter.

Tropes used in DDD include:

Artificial Limbs: The prosthetics of Karyou, which are true demons. He occasionally loans one out to Arika, whose arm was eaten off by his sister.
Badass Normal: Touma Matou, aka "Tomato-san" (Nobody is brave enough to utter this out loud). Police officer and firm believer in More Dakka; she probably would be able to take on most Agonists and survive.
Body Horror: Some Agonists become....nasty looking.
Cognizant Limbs
Demon Hunting: Arika at night and with the Arm of Hatred.
Dude Looks Like a Lady: Karyou Kirie
Expy: Karyou is very similar to Merem Solomon of Tsukihime in terms of situation.
Eyes of Gold: Arika's sister, Ishizue, has this. She earns them; as she's one of the most powerful and insane of the Agonists.
I'm a Humanitarian: Several Agonists.
Lemony Narrator: Arika.
Power Born of Madness: Agonist Syndrome, all the way.
Shout-Out: Arika mutters to himself that only an idiot burglar would go to the police if they discovered the family they're robbing was murdered. This happened in Kara no Kyoukai. Arika isn't one for compassion, btw.