One of the most popular manga of this time, Attack on Titan definitively deserves the hype.

The story starts with a strong mystery aspect, that culminates into one of the best plot twists ever made. As the story progresses it becomes grayer and grayer, to a point where no one is truly good or evil, and there is no clear moral path. It takes a very realistic approach to conflict, and its characters are very diverse in ideologies.

When I started this series, in many ways, as someone who has beliefs in some moral principles, I found this manga to be challenging to read. It is very cruel to its characters, and more often than not deals with the idea that a cruel iron fist should be preferred to mercy, and that inhumane actions may be the right way to go... an idea that ends being thoroughly, extensively deconstructed without ever being sweetened. And that is pretty outstanding.

For the rare ones who claim Attack on Titan promotes a fascist ideology, I believe it is not the case, you just have to see how the events of the series are depicted suggest.

An incredibly gray story, with many fascist elements either evoked or used but subverted. An incredible plot twist. And gray, very human characters. It's an intense read at times, but it is one of the best stories I know.