Phantasm Phenomenon of Memoria-Noise

Somewhat unnoticed beneath the sheer popularity of Boogiepop and the flashy fantasy trappings of the Jiken series, Kouhei Kadano has been quietly working on the Soul Drop series, producing volumes at a significantly faster rate than either of his other ongoing works.
It's not a series that draws attention to itself; published by Non Magazine's novel line (Non is a women's magazine, I think) it boasts bland illustrations (that, to their credit, capture the personalities well) and stock cover dress, and back cover copy that somehow fails to mention what I'd consider the fucking hook.
The covers do vaguely mention that it involves two insurance agents chasing a mysterious man known only as Papercut - a man who steals seemingly insignificant items that are, unbeknownst to the owners, of equal value to their lives.
What the covers fail to mention is that one of the agents IS A ROBOT.
How you can have a god damn robot detective in your book and not god damn mention it is fucking beyond me. I suppose they wish to avoid distorting expectations - this is a book that thrives on ensemble casts, with an intangible villain who never actually meets the supposed main characters, and whose actual motives remain something of a mystery to everyone but himself.
Hell, this volume, the second one, complicates describing things dramatically by adding a new character into the mix, one who manages to be instantly so compelling he effectively feels like the actual main character of the series, one who simply was too busy to show up for the first volume.
I think there was a mystery in here, and it worked reasonably well, without ever getting bogged down in tedious deduction; but Kadano has the sense to make his mystery play thematically into what we're learning about the central characters.
I've written often about Kadano's unique grasp of character, and the refreshingly subdued narrative neatly puts this skill out front, allowing it to carry the book. At least, carry it up until the robot starts punching grenades back at people.
Nothing ever works on only one level, and nothing is ever spelled out for us completely; a scene where one character describes her brother ostensibly exists to sketch in their relationship, but the responses of the characters around her tell us something about each of them, her own response tells us something about her brother, and the brief description of her behavior: '"I hate him," she said, quickly. Too quickly,' is a glancing blow that tells you a lot without ever really giving you the truth.
The first two books here have effectively crystallized what I like about Kouhei Kadano; they may well be his best work.