As of the time I'm writing this the last episode of Ranpo Kitan has finished airing. This series is genuinely decent. Just decent. If you're just looking to find a 'masterpiece' this show is not for you.
Also I'll just go ahead and tell you that as you go into this series, expect all sort of disturbing, disgusting things. The series is very gory and it's themes and undertones aren't exactly child friendly. So just a heads up, the show is messed up from day 1.
It's biggest flaws include it's story and character development. There are continuous plot holes that by rules I cannot discuss
now, but they take away from the overall quality of the show especially from the first few episodes.
This show is also somewhat confusing for some viewers as some episodes leave you with questions and leave you wondering what's even going on. The way the plot progresses in the first half is rather mediocre and I'd even go as far to say odd. It didn't feel like much effort was put into this part and even by the end of the series the first 5 or so episodes feel irrelevant to the overall scope of things. By episode 6, the show overall picks up in quality and some very interesting events happen. From episode 6 forward the main focus of the anime shifts into a new, darker arc that finally introduces decent character development (but said development is only revealed in the final episodes) and events that were very....different from most other anime. Side characters also become important to the overall plot and events of the story and help the plot pick up. I don't feel like this series was rushed at all unlike some other series here. It had a somewhat 'open' finale but at the same time was somehow 'conclusive'.
While I'm at that, some of the antagonist's motivations are confusing and if you think logically while watching a series you'll probably pick up on. Just a heads up.
Art : The visuals are amazing for this show, I have to say. The scenery looks beautiful and conveys exactly what the writer was thinking. The character design is also very appealing but "generic" for most of the male lead. Definitely is different in terms of the way the art presents itself. During dialogue and flashbacks even the artwork is constantly changing. Almost sort of like the entire series is a play for the viewers even.
If you're interested in a "gory, action, thriller" anime that'll make you say WTF, Ranpo Kitan is what you're looking for.