Read: The Way of Shadows
The Way of the Shadows is the first in such a trilogy; and it is also the author’s debut, Brent Weeks first novel. For a debut novel it is quite good.
The trilogy is kind of a male version of Canavan’s Black Magician Trilogy. A young boy, an orphan, is apprenticed to a magician, an assassin with magical powers. We learn about the hardships of the apprenticeship, the forming of new skills and everything culminates in a war.
While this more overarching theme is not that original the actual plot details are more promising. Weeks does not spare the unpleasant details. Nothing is sugar coated. The writing style is a little rough, though. You could say that neither content nor form is (very) polished.
I hope the dialogs, the description of the environment, geography, society, and politics, and the general structure (the perspective changes quite often) of the subsequent novels improve a bit (there seem to be some quite interesting ideas hidden). On the other hand, the plot details, the willingness to touch rather sensitive topics, and the willingness to kill off a character are just fine. In particular this last point adds to the suspense. It is not that often that a major (or even a minor) character in a fantasy novel is killed off. Weeks proves that everything may happen and the survival of a character cannot be taken for granted.