So today marks the day I finally finished reading Akuma no Riddle. I'm Taking this from the perspective of someone who has both watched the anime and read the manga. And I can say without a doubt that the manga portrays it better (as to be expected).
The character development in the manga is very well written, and I felt that the characters and their personalities all helped to pull the story together. But while most of the characters was written really well, I do got a couple complaints. One being that While Haru Ichinose and her personality was very well written, it really doesn't give any explanation as to why she got the scars. And then we got Azuma Tokaku which while also being well written, doesn't get much of an explanation to her background. And I feel like the manga could've been much better if they would've just spent another couple chapters to build up their characters as a whole. But if someone asked me if they should read this, I would recommend this manga.