"Why must one die?" Is being immortal a gift or a curse?

One day, our main character Nagai, Kei finds out the wrong way(and only way) that he's an immortal being with supernatural powers, which is not only bad since the government is after all "Ajins"(Immortals) for experimental purposes but because he's one of the few hundred Ajin's in the world.
His head has a price now, and his mysterious abilities make him the perfect target for everyone around him. Who will remain his friend and who will betray him?

Kei is given a quick introduction into a very realistic world.
Ajin is filled with psychological and existential issues that question society's morals when dealing with this new "race". How would society react to these immortal people? It has many similarities to our world and it's a way to feel empathy with the characters and that part of the story since we too deal with issues like racism and discrimination.

The main character goes through many ideology changes throughout the manga as he fights for his freedom and "survival". His best friend plays a big part in his new life, and both are given great character development. Other characters are also well developed to show the other side of the coin, the cruel humans and the typical greedy government.

The art is great. The gore elements that are added for shock value are superb. Everything is really well drawn and the style blends well with the story. All designs and especially the Ajin's mysterious "ability" make the story more engaging.

The seriousness of this manga describes very well how we humans act in face of death and pain. People turn selfish and hateful when pushed to the limit, add a mystery and supernatural concept into the mix and you have the story of an immortal kid with a strange power.