As per the title, I can't remember the title of this book that I read some years ago (10ish I guess).

As far as I remember, the story starts with the protagonist being hired to kill some member of elite society, and then the book is all about him running away, exploring different areas of the planet and finding allies and enemies.

He also has an implant / enhanced technologies inside his body that help him kill and run away. I remember once he blew up his hand / fingers in order to produce some sort of explosion.

At the end, the plot twist is that he hired himself (or it might be that he killed himself and he's a clone? I don't know).

Any suggestion which book it might be? I've tried everything but nothing so far.