I would be surprised if anyone does not consider this a masterpiece. This might be overkill but I'm sure this is one of them.
I tensed up during the journey and I felt empty and sad nearing the end of the story.
Philosophy and human character are so strong. What happened to the twins is truly tragic. For me, Johan is the most complicated character ever made in the manga's history. Maybe everyone can find him easy to understand, in a sense, but not exactly. He is embodiment from nothingness.
I do not advise readers to see them all from the results of their actions but from their own human character. This may be presented with many bloody murder tragedies but the brutality is seen from a human perspective.