My favorite is Naoki Urasawa's Monster

You get people talking about 21st Century Boys and Pluto, but Monster is just a roller-coaster of drama

The short version is that it follows an up-and-coming Japanese surgeon in Germany, next in line to become head of surgery at a prestigious hospital. His ethics are put to the test when two patients arrive with grievous injuries, the first is a young boy who's been shot in the head and left for dead with the rest of his family, the second is the mayor who has an aneurysm on the verge of bursting

The doctor is warned that if he doesn't operate on the mayor, his career is in jeopardy, but he knows that if he doesn't operate on the boy he's likely to die

He chooses the boy, the mayor ends up dying and his career is left in tatters. His fiancee dumps him, the other doctors ostracize him and he's basically all but blacklisted.

In a drunken haze, he goes to the room of the boy who's life he saved, hoping for a sign that he made the right choice, but the boy is still in a coma.

In a fit of rage, he curses the other doctors, wishing that they would suffer like he has.

The next day, he arrives for his shift at the hospital... and the other surgeons are dead, poisoned

After being interrogated and cleared, he returns to the hospital with the news that he's now set to become the head of surgery

Life is finally looking back up, except the boy in the coma is missing and no one knows how

At least until the boy shows back up to tell the doctor exactly what happened.

The boy had killed his own family and poisoned the other doctors as a way of thanking him for saving his life, letting him go on to keep killing and getting away with it

The doctor is left devastated, he swore himself to the preservation of life, but now that's been turned against him

He steels himself and swears to track down the boy by any means necessary, even if that means violating his deepest beliefs and killing him

This is only the first few chapters by-the-by and it escalates and gets even wilder and more intense

I love it so much