The thirtieth comic: #647 Monster
This was its own rollercoaster. Monster is a crime thriller, with a brain surgeon following the trail of a serial killer... or someone who manages to get others to do that killing. The story would work as a book, but the graphics add here, especially for the effect of seeing Johan, the aforementioned serial killer.
Although initially focused on Dr Tenma, on the run from the law while trying to prevent further killings, the cast slowly expands to include others affected by Johan's action, looking to find or stop him. Most of them are affected by the orphanage that made Johan what he is, and the mysteries surrounding it.
There's some mystery here, surrounding what happened, but the revelations are at such a pace that there aren't a lot of mysteries that really plague you. It's far more about the journey to find Johan and how different people deal with this. It's certainly bloody - something manga can get away with more easily, but it suits the tone of the story. It's been an interesting read.