This is among the worst manga I've read recently and I've dropped several.
Ranting:
The plot is ridiculous, the defenses are supposed to be some kind of detective mystery solving yet are no more than his search for an item and them miraculously coming up with a tale that makes sense and voila! he's innocent!!? no logic, no deduction, no clues, nothing, he learns the truth by osmosis? how is that interesting? Furthermore, the "dark-matter" only envelops sinners yet they are all innocent and have it, the devils can't affect the real world yet they do so all the time, and where the hell is god in all this? watching and having a laugh? by the time the author realized he had forgotten about the "good" side God had already forsaken who knows how many souls to hell. Not to mention the representative of "good" is a renegade nun excommunicated by the church..., so again, where is god?
And the fights? how lame can they be that the shinigamis can't kill someone with no powers? talking about a one-sided fight, he has no powers, the shinigami need no authorization or judgement or due process to condemn souls, if he looses not only the accused goes to hell but he also becomes dust¿?, on the other hand, the shinigami if they loose... nothing happens to them, they have limitless powers, other shinigami allies and all the underworld in their back and go unpunished if putting innocents in danger yet they are in charge of punishing the sinners... even so, he wins every single time saving the poor soul at the last moment when falling to hell... cut the crap.
Devil tennis, Holy cars with gadgets, evil devils that turn good for no reason, the list is long, it doesn't take itself seriously and it doesn't have a pinch of sense.
Then we have the main char, the son of the devil king who with no real reason turned out to be sainter than Maria Theresa, must have been his uprising... or his ridiculous sidekick that can't be more annoying and ain't funny at all.
In a sum, I didn't expected a deep plot or deep mysteries or refinement in the characters in a shounen manga but a little sense and likable chars is a must for me. And I dropped it so maybe some of the things above are answered (as usual in retrospective, a solid story makes sense from the get go, it doesn't try to make sense of things latter as it goes), in any case, it failed to hook me at all and it took some patience to read till ch15 that some said it's were it gets good... but it didn't get any better, so in my eyes, a failure.