Yarvi is the son of a king, promised to the scholars of the realm due to his disability. But when his father and brother are killed, it is up to him to take the throne and avenge them. That doesn't go so well, and he winds up a slave, vowing to avenge not only his family, but himself. The journey back to his kingdom hones him into the man he needs to be in order to kill his uncle and take back his throne. 
 Usually when authors are compared to George R.R. Martin I take it with as much salt as I would if they were compared to J.R.R. Tolkien, but in this case, the comparison is apt. Half a King is easily comparable to A Song of Ice and Fire, with a similar level of political intrigue and violence, though with fewer players (and no sex). Abercrombie is a master of the grimdark, yet the dark elements are never gratuitous or dark for the sake of being dark; everything that Yarvi endures hones his mind and will into the weapons they need to be to complete his quest. 
 The other characters are also wonderfully written, especially Yarvi's fellow slaves; the banter between them as they travel back to Yarvi's home frequently made me laugh out loud (and then read passages to my husband, which is always a mark that I'm enjoying a book). 
 It's been a long time since I read a book with so much drastic yet well-written character development, and I thoroughly enjoyed it.